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To download our step-by-step installation instructions visit http://www.marshalls.co.uk/dam-svc/AssetStore/Slot-Drain-Installation-Guide-11477.pdf. DRAINAGE MEETING JOINT DISTRICT MARSHALL-STORY#1 JUNE 24, 2014 The Story and Marshall County Drainage District Trustees met at the West Marshall High School Auditorium in State Center, IA to present the Preliminary Engineering Report to and receive input from land owners in Joint Drainage District Marshall-Story #1, Story County controlling.
POST a QUESTION or COMMENT about brick wall weep inserts & where to buy masonry wall weep opening inserts & products for shell drains.
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Weep holes in brick walls:
Here we give construction specifications & details for proper location, flashing, & protection of weep holes or drain openings & vents in brick or other masonry veneer walls. We explain how these weep or vent openings in brick walls work, where and how they should be installed, and what special products such as opening screens & flashings are available.
This article series explains the purpose of drainage openings & rain screens in solid brick walls and in some brick veneer walls: brick wall weep holes and recommends their use in new construction and in some brick wall repairs or retrofits
. Weep holes in building exterior masonry walls (brick or stone) are a drainage system that is used in cavity wall or rain-screen wall construction methods to get rid of water that has penetrated the outer wall skin or surface.
We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need. 
Weep Holes in Brick Veneer & other Masonry Veneer WallsBrick veneer construction [and some other masonry veneer construction such as thin stone over wood framed walls] incorporates a drainagecavity to deter water penetration into the building. 
This air space creates a physical separation between the brick wythe and the inner steel stud wall.
 When the wind-driven rain penetrates the veneer wythe, the cavity allows the water to drain down the back face of the brick. This water is then collected at the base of the wall by flashing and channeled out to the exterior through weep holes. (Arumala 2007)
Watch out: Both structural brick walls and veneer brick (or stone) walls may be designed either as a barrier wall or a cavity/rain-screen wall. Before you can evaluate the condition of a wall you need to understand how it was built and whether or not the as-built matches the as-designed conception of the wall.
Our page top sketch, courtesy of Carson Dunlop Associates, a Toronto home inspection & education firm, shows both the reasons for and the typical design details used in weep openings on brick walls.
[Click to enlarge any image].
The beautiful Flemish-bond structural brick wall (left) on the Vassar College Campus was constructed with very subtle drain or weep openings at the wall bottom. It has survived intact even though the building is located in a seasonally wet and freezing climate.
Article Series ContentsBRICK WALL DRAINAGE WEEP HOLES
Watch out: In February 2016 in the U.K. The Telegraph reported that the Cavity Wall Insulation Victims Alliance (CWIVA) was lobbying both industry and government to obtain relief from insulation companies who were selling this bad approach to building energy savings by representing that their insulation was 'government-backed' - it was not and it is not.
Some of these news reports 'mould in wall cavities is caused by insulation' describe a real problem but do not necessarily offer a correct explanation of the cause of the mould contamination. Insulation does not itself cause mould growth. Mould spores are present everywhere, all the time, in air. But when conditions are right, particularly trapped moisture and perhaps temperature, mould growth will be encouraged in and on buildings.
Since the mid 1980's building scientists have known stressed that air leaks into and out of wall cavities at penetrations (openings for receptacles, switches, wires, pipes) is a particular source of moisture problems.
If we combine leaks or moisture with improper placement of insulation, such as pumping or blowing styrofoam bead or other insulation into the air space between a brick veneer wall and the building's structural (usually wood-framed) wall, then yes, that's a recipe for trouble. Brick veneer walls are not waterproof and must be designed to permit water to drain out of the wall rather than into the wall interior.
This article provides details about the importance of providing proper drainage for brick veneer walls.
Definition & Images of Veneer Wall or Masonry Wall Weep OpeningsWeep openings are drainage holes left in the face of a brick veneer wall [and possibly some other constructions] in order to allow water that has penetrated the wall to escape downwards through the wall cavity and out to the exterior of the wall surface through the weep openings.

 As will be explained later, I think the weep openings in the veneer wall shown above, though properly located, are probably not working.
This escape passage and wall design are a method for reducing water intrusion into the structure interior. According to the Masonry Design Manual, weep holes are
Openings placed in mortar joints of facing materials at the level of flashing, to permit the escape of moisture, or openings in retaining walls to permit water to escape.
Above we illustrate the most basic brick wall weep opening.
To diagnose a building water entry or moisture problem originating at its exterior walls we must first understand the construction concepts that were used to build that wall: two very different concepts apply, though they often appear mixed or even confused in buildings: barrier wall construction methods (the wall exterior skin keeps out water) and cavity or rain-screen wall construction (the wall is designed to handle and get rid of water that penetrates the outer skin).
See WALL CONSTRUCTION BARRIER vs CAVITY for definitions and explanations of barrier wall construction compared with cavity / rain screen exterior wall construction methods, objectives, and damage vulnerabilities.
Below we show a brick wall (a veneer in this case) with weep openings at regular intervals at two heights above ground level.
Below is a close up of one of the drainage openings.
Veneer wall weep or drain openings are placed at least at the very bottom of a brick veneer wall cavity and sometimes as vents openings are placed higher in the wall in some designs.
For the wall shown in the photos just above, we suspect that an air space behind the veneer does not extend lower than the weep holes in our photos. Why? The lower wall is solid masonry construction with no air space rather than frame construction. 
The lower brick courses were laid tight, with no cavity at all, against a solid concrete or masonry block foundation wall, thus forming a solid composite masonry wall.
 Typical Construction Specification for Brick Veneer Wall Containing Weep or Drain Openings & Wall Cavity VentsHere are three examples of wall cavity vent and weep opening specifications adapted from the Brick Industry Association (BIA), our industry expert source, and from two example construction specifications for brick veneer walls that offer more details.
Note: the specifications for any particular building project should be made by a qualified design professional such as a licensed professional engineer or licensed architect. 
Weep Hole Wall Vent Construction Specification Example #1 - BIAThe Brick Industry Association recommends veneer wall weep opening specifications as follows:
Weeps:
 Open head joint weeps spaced at no more than 24 in. (610 mm) o.c. recommended
Most building codes permit weeps no less than 3 /16 in. (4.8 mm) diameter and spaced no more than 33 in. (838 mm) o.c.
Wick and tube weep spacing recommended at no more than 16 in. (406 mm) o.c.- BIA 28B cited below.
Above, these weep openings are properly located: above the upper surface of the wall bottom flashing, and they might meet the BIA's 3/16' (4.8mm) diameter, but in my opinion they are inadequate.
At BRICK VENEER WEEPS BLOCKED or MISSING we show that these tiny tubes inserted as veneer wall drains were mostly blocked by mud placed by mud-dauber wasps. Little wall-bottom tubes are also very easily blocked by falling mortar and debris in the wall cavity. Good location, weak weeps.
At BRICK WALL DRAINAGE, FLASHING, VENTILATION PRODUCTS we illustrate a taller, blockage-resistant PVC product that provides better veneer wall drainage opening protection, letting water out while preventing insect intrusion.
Weep Hole Wall Vent Construction Specification Example #2Wall shall use pre-formed control joints using rubber material. Provide with corner and tee accessories and fused joints. 
Weep openings: use molded PVC grilles that are insect resistant, located above-grade and not blockedInstall weeps in veneer walls at 16' (400 mm) on center horizontally above through-wall flashing, above shelf angles and lintels and at bottom of walls
Install cavity vents in veneer walls at 16' (400 mm) on center horizontally below shelf angles and lintels and at top of walls.
Install cavity mortar diverter at base of cavity as recommended by manufacturer to prevent mortar droppings from blocking weep/cavity vents.
Do not permit mortar to drop or accumulate into cavity air space or to plug weep/cavity vents. 
Wall cavity mortar control: Semi-rigid polyethylene or polyester mesh panels, sized to thickness of wall cavity, and designed to prevent mortar droppings from clogging weep openings and cavity vents and designed to allow proper cavity drainage
Venting a Veneer Wall Supported on a FoundationHuuuge casino free chips links twitter. [Click to enlarge any image]
Above: Brick veneer wall construction details showing weep openings immediately above flashing that is in turn atop bottom brick course of a brick veneer wall constructed over a steel stud cavity wall. These details are for a brick veneer wall that rests atop a masonry foundation.
This illustration is adapted from BIA Technical Notes 28B, Figure 1 as used in Arumala 2007 cited below. Critical wall bottom flashing is shown in red, brick veneer weep opening locations above the horizontal portion of that flashing are shown in green, and house-wrap / water barrier fabric(s) are shown in dark gray.

Watch out: Less evident in our sketch but important: the water barrier affixed to the wall sheathing should extend over the top of the wall bottom flashing, not behind it.
Otherwise water in the wall cavity may pass behind the bottom flashing and thus will fail to drain from the wall cavity.
Venting A Veneer Wall Supported by Steel LintelBelow: Brick veneer wall construction details showing the location of weep openings immediately above wall bottom flashing that is in turn immediately above the upper surface of the supporting steel lintel in a lintel-supported brick veneer wall design.
[Click to enlarge any image]
Notice that when the brick veneer is supported by a steel lintel, the weep openings are immediately over the wall bottom flashing that is in turn immediately over the upper surface of the supporting steel lintel. 
This illustration is adapted from Figure 3, 'A Typical Section of a Brick Veneer Wall with Steel Stud Backup Wall' - Arumala (2007)
Weep openings & vents in upper levels of brick veneer wallsAs our photograph above illustrates, in tall brick veneer walls additional weep openings and air vent openings may be specified by the architect/engineer for placement higher in the wall.
Air, Cavity & Weep Hole Wall Vent Specification Example #3Air Vents: Flexible ultra violet resistant polypropylene co-polymer DA1006 Cell Vent by Dur-O-Wal Inc., 7777 Washington Village Dr., Ste. 130, Dayton, OH
45459, (888) 977.9600, www.dur-o-wal.com.Size: Height 2-1/2 inch maximum except as indicated otherwise, by full width of brick.
Color: To match mortar color.
Weep Vents: Flexible ultra violet stable recycled polyester mesh, rectangular shape by Mortar Net USA Ltd, 541 S. Lake St., Gary, IN 46403, (800) 664-6638,
www.mortarnet.com, CavClear Weep Vents by Archovations, Inc., PO Box 241, Hudson, WI 54016, (888) 436-2620, www.cavclear.com.Size: Height 2-1/2 inch maximum except as indicated otherwise, by full width of Brick.
Color: To match mortar color.
Cavity Wall Mortar Net: Lightweight polyethylene, 90 percent open woven mesh by Mortar Net USA Ltd, 541 South Lake Street, Gary, IN 46403, (800) -664-6638,
www.mortarnet.com. or CavClear Masonry Mat by Archovations, Inc., PO Box 241, Hudson, WI 54016, (888) 436-2620, www.cavclear.com.Size: Height 10 inches, thickness as required to fill cavity.
Size: Full height of wall, thickness as required to fill cavity
Weep Holes: Form weep holes in mortar joints of exterior wythe of cavity walls at bottom of cavity over foundations, bond beams, through wall flashings, and other water stops in wall.
 Form weep holes by leaving head joint free and clean of mortar, and raking out bed joint at weep hole.
 Space weep holes approximately 24 inches oc. Keep weep holes free of mortar droppings and other obstructions.
Pointing & Cleaning at End of Wall Construction At completion of masonry Work, fill holes in joints (except weep holes) and tool.
Building Code Requirements for Brick, Stone or other Veneer Wall Drains & VentsU.S. IRC, (2012) International Residential Code, Foundations, R703 Exterior Covering 
Sketch: brick or other masonry veneer wall construction details showing air space, flashing, weep openings, adapted from 2012 IRC cited below. 
[Click to enlarge any image]
R703.1.1 Water Resistance The exterior wall envelope shall be designed and constructed in a manner that prevents the accumulation of water within the wall assembly by providing a water-resistant barrier behind the exterior veneer as required by Section R703.2 and a means of draining to the exterior water that enters the assembly.
Protection against condensation in the exterior wall assembly shall be provided in accordance with Section R702.7 of this code.
Exceptions:
1. A weather-resistant exterior wall envelope shall not be required over concrete or masonry walls designed in accordance with Chapter 6 and flashed according to Section R703.7 or R703.8.
2. Compliance with the requirements for a means of drainage, and the requirements of Sections R703.2 and R703.8, shall not be required for an exterior wall envelope that has been demonstrated to resist wind-driven rain through testing of the exterior wall envelope, including joints, penetrations and intersections with dissimilar materials, in accordance with ASTM E 331 under the following conditions:
2.1. Exterior wall envelope test assemblies shall include at least one opening, one control joint, one wall/eave interface and one wall sill. All tested openings and penetrations shall be representative of the intended end-use configuration.
2.2. Exterior wall envelope test assemblies shall be at least 4 feet by 8 feet (1219 mm by 2438 mm) in size.
2.3. Exterior wall assemblies shall be tested at a minimum differential pressure of 6.24 pounds per square foot (299 Pa).
2.4. Exterior wall envelope assemblies shall be subjected to the minimum test exposure for a minimum of 2 hours.
The exterior wall envelope design shall be considered to resist wind-driven rain where the results of testing indicate that water did not penetrate control joints in the exterior wall envelope, joints at the perimeter of openings penetration or intersections of terminations with dissimilar materials.-
R703.7 Stone and Masonry Veneer, GeneralStone and masonry veneer shall be installed in accordance with this chapter, Table R703.4 and Figure R703.7. 
These veneers installed over a backing of wood or cold-formed steel shall be limited to the first story above-grade plane and shall not exceed 5 inches (127 mm) in thickness. 
See Section R602.10 for wall bracing requirements for masonry veneer for wood-framed construction and Section R603.9.5 for wall bracing requirements for masonry veneer for cold-formed steel construction.
Exceptions:
For all buildings in Seismic Design Categories A, B and C, exterior stone or masonry veneer, as specified in Table R703.7(1), with a backing of wood or steel framing shall be permitted to the height specified in Table R703.7(1) above a noncombustible foundation.
For detached one- or two-family dwellings in Seismic Design Categories D0, D1 and D2, exterior stone or masonry veneer, as specified in Table R703.7(2), with a backing of wood framing shall be permitted to the height specified in Table R703.7(2) above a noncombustible foundation.
Brick Veneer Wall & Curtain Wall Venting & ResearchArumala, Joseph O. 'Brick Veneer Steel Stud Wall Systems: State-of-the-Art.' The Masonry Society Journal (2007): 9-19. Illustrations used in the article above include adaptations from BIA Technical Notes 28B Figure 1 as used in this article. ©IAP 2016
Arumala, J. O. and Brown, R. H., 'Performance Evaluationof Brick Veneer with Steel Stud Backup', Department ofCivil Engineering, Clemson University, Clemson, SouthCarolina, April 1982.
Brick Industry Association, 'Technical Notes on Brick Construction', Brick Industry Association, 1850 Centennial Park DriveSuite 301Reston, Virginia 20191703-620-0010brickinfo@bia.org, Website: www.gobrick.com, retrieved 2016/06/21,original source: http://www.gobrick.com/Technical-Notes Brick Industry Association, [BIA], 'Brick Veneer / Steel Stud Walls, 28B', [PDF] Brick Industry Association, op.cit. (December 2005), retrieved 2016/06/21, original source: http://gobrick.com/Portals/25/docs/Technical%20Notes/TN28B.pdf Excerpt included in the article above
BIA, 'Brick Veneer Construction: Basics of Resisting Water Penetration in Residential Construction', [PDF] Brick Industry Association, op.cit. (Issue 1), retrieved 2016/06/21, original source: http://www.gobrick.com/Portals/25/docs/Publications/Builder%20Notes/Builder_Notes_1.pdf
Excerpt: 
Through-wall flashing is animpermeable membrane placed in thewall that extends from the sheathing,across the air space, and all the wayto the exterior of the brickwork (seeFigure 1). One should place flashingat all points where the air space isclosed off. 
Model building codesrequire flashing at the foundation,above window and door heads, atwindow sills, and where the roof ofa one-story wing meets a two-storybrick veneer wall. 
..
Flashing should extend from theoutside face of the veneer, throughthe thickness of the brick veneer,across the air space to the backing,and then up at least 8 inches. Theflashing should either extend up behind the water-resistant barrieror should be attached to its surfacewith a termination bar. Flashing heldback from the outside of the brickveneer— even just 1/2 inch—couldallow water to re-enter the wall. 
BIA, 'Lo Esencial sobre la Construcción de Revestimiento de Ladrillos y Lista de Control de Trabajo', retrieved 2016/06/21 original source http://www.gobrick.com/Portals/25/docs/Publications/Builder%20Notes/Builder_Notes_Spanish_Issue2.pdf
BIA, 'Brick Masonry Cavity Walls: Introduction,' Technical Notes on Brick Construction No. 21, Rev., Brick Industry association, Reston, VA., 1998.
BIA, 'Brick Veneer/Stud Panel Walls,' Technical Notes on Brick Construction No. 28B, Rev. II, Brick Industry association, Reston, VA., 1999.
Choi, Edmund CC, and Zhihong Wang. 'Study on pressure-equalization of curtain wall systems.' Journal of Wind Engineering and Industrial Aerodynamics 73, no. 3 (1998): 251-266.
Abstract:
In recent years, aluminium-curtain-wall systems are often used in southeast Asia. Many of these curtain-wall systems can be classified as a two-barrier system with a front-panel (the rainscreen) and the back-panel (the air barrier). The back-panels of such systems are usually thin and flexible. 
Compared with the brick or brick-veneer rainscreen walls, where the back-panels are very rigid, the pressure-equalization characteristics are expected to be quite different. To improve on the understanding of the behaviour of such systems and to evaluate design parameters, full-scale measurements were carried out. 
A numerical model which takes into account the flexibility of the back-panel has been developed for the prediction of cavity pressure in curtain walls. The results based on this model show good agreement with those obtained from full-scale experiments.
Drysdale, R.G. and Kluge, A., 'A Summary of Performanceof Brick Veneer/Steel Stud Wall Systems Subject to Temperature,Air Pressure and Vapor Pressure Differential,'Seminar on Brick Veneer Wall Systems, Toronto, Ontario,Canada, June 1989.
ICBO 1997, Uniform Building Code, International Conferenceof Building Officials, Whittier, CA, 1997.
IRC, (2012) International Residential Code, Foundations, Chapter 7, Wall Covering [PDF] 
Keeton, B., 'Prevent Water Intrusion and Minimize Exposureto Claims by Building with Mold in Mind' ConstructionExecutive, vol. 13, No. 7, pg 46-48, Association ofBuilders and Contractors, 4250 North Fairfax Drive, 9thFloor, Arlington, Virginia 22203, June 2004.
Masonry Standards Joint Committee (MSJC), 'BuildingCode Requirements for Masonry Structures', (ACI 530-05/ASCE 5-05/TMS 402-05), American Concrete Institute;Structural Engineering Institute of the American Society ofCivil Engineers; The Masonry Society, Boulder CO, 2005.
McGinley, Mark W., 'An Alternative Design for BrickVeneer Steel Stud Walls', The Masonry Society Journal,The Masonry Society, Vol. 18, Number 2 pp. 9-22, December2000.
Piper, Richard S., and Russell J. Kenney. 'Brick Veneer Walls-Proposed Details to Address Common Air and Water Penetration Problems.' [PDF] In Masonry: Design and Construction, Problems and Repair. ASTM International, 1993., retrieved 2016/06/21, original source: http://www.masonrysociety.org/TMSJournal/Vol.%2025.%20No.%201/P009%202004-10.pdf
Reneckis, Dziugas, James M. LaFave, and Wade M. Clarke. 'Out-of-plane performance of brick veneer walls on wood frame construction.' Engineering structures 26, no. 8 (2004): 1027-1042.
Abstract:
Full-scale brick veneer wall panel specimens, representing typical residential construction practice, were investigated under static and dynamic out-of-plane lateral loading on a shake table. The tests captured the overall performance of the wall system, including interaction and load-sharing between the brick masonry veneer, corrugated sheet metal ties, and wood frame backup. 
The tests evaluated the effects of two different tie installation methods, as well as a veneer-to-backup connection repair using post-installed mechanical anchors. The progression of system damage was noted up until partial collapse of the veneer walls; tie stiffness and strength were found to significantly affect wall performance at all stages of behavior. 
Analytical models for veneer wall systems are being developed based on these experiments to further study the vulnerability of this type of construction.
Straube, J. F., and E. F. P. Burnett. 'Rain control and screened wall systems.' In Proc. 7th Conf. on Building Science and Technology. Durability of Buildings. Design, Maintenance, Codes and Practices. Toronto, pp. 20-21. 1997.
Treshsel, H. R., editor, 'Moisture Control in Buildings',ASTM manual series MNL 18, 1994 American Society forTesting and Materials (ASTM), pp. 224-225, 1994.
Van Straaten, Randy. 'Measurement of ventilation and drying of vinyl siding and brick clad wall assemblies.' (2004).
Abstract: 
Control of moisture and heat flow through building enclosure assemblies is a critical component of overall building performance. This thesis shows that significant drying of moisture in wall assemblies is possible and that ventilation of cladding significantly increases the rate of drying in some assemblies without having detrimental impact on the enclosures thermal performance.
A review found that thermal and moisture buoyancy, wind pressure gradients and mechanical equipment drive ventilation airflow. This ventilation flow can theoretically increase the effective water vapour permeance and thermal conductivity. Ventilation has the potential to increase outward drying through relatively impermeable claddings at the low flows expected to occur in service.
 The impact on thermal conductance is much less. A methodology for assessing the complicated airflow resistance characteristics of lap sidings was developed and applied to a representative vinyl siding. Field drying studies showed that the sample tested is well ventilated. Field brick veneer clad wall samples were also tested for system airflow resistance over a range of driving pressures.
Theoretical predictions under-estimated the measured flow rate for given steady driving air pressures. Measurements of naturally driven cavity air speeds and smoke pencil testing showed that flow rates were commonly occurring that would in theory significantly affect the hygrothermal performance of the walls. This was confirmed with field drying studies. A field drying study of east-facing test wall with vinyl siding and brick veneer cladding was conducted in Waterloo, Ontario, Canada.
Significant amounts of drying and inward moisture redistribution were measured. Wall sheathing dried quickly in hot summer conditions but in some cases significant inward driven moisture flow occurred. In cool and cold weather the wall dried more slowly and much less moisture moved inward. Increased cladding ventilation significantly increased drying rates and reduced internal wall assembly moisture levels.
It was concluded that cladding ventilation acts to increase the effective vapour permeance of cladding and to reduce solar driven inward vapour drives. The use of spun bonded polyolefin sheathing membrane in lieu of #15 asphalt impregnated felt was found to improved hygrothermal performance in the test walls. 
The difference observed was concluded to be due to the higher vapour permeance of the spun bonded polyolefin and may not hold for wall assemblies with lower permeance sheathings (e. g. oriented strand board and foam plastic). Walls clad with vinyl siding dried faster than those clad with brick veneer. It was concluded that the vinyl siding is a well ventilated cladding system.
Williams, Mark F., and Barbara Lamp Williams. 'Water Intrusion in Barrier and Cavity/Rain Screen Walls.' In Water in Exterior Building Walls: Problems and Solutions. ASTM International, 1991.
Also see REFERENCES for this article
Where do the Brick Wall Drainage Openings (Weep holes) Belong?Where do the brick wall weep holes go? This topic has moved to a separate article now found at BRICK VENEER WALL WEEP HOLE LOCATION
Damaged Brick Veneer Walls - Blocked or Missing Brick Veneer Weep OpeningsDetails of this topic are now at BRICK VENEER WEEPS BLOCKED or MISSING.
Not All Brick Veneers Lacking Drainage are Damaged - Some of these are Barrier Walls not Cavity / Rain Screen Walls
Brick Veneer Wall Through-Ventilation - Airflow Removes Moisture?This discussion has moved to BRICK VENEER WALL THROUGH-VENTILATION
Brick Veneer Wall Leakage Problems in Buildings Exposed to FloodingPlease see the new article at BRICK VENEER WALL LEAKS in FLOOD PRONE AREAS
Guide to Brick Wall Drainage Opening, Flashing & Ventilation ProductsMarshalls Slot DrainPlease see BRICK WALL DRAIN, FLASHING, VENT SOURCES
Shown above: A Tamlyn Building Products brick vent screen discussed in the article linked-to just above.

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Technical Reviewers & ReferencesHowell, Jeff, 'Could the cavity-wall insulation scandal rival PPI?', The Telegraph, 16 February 2015, original source: Could the cavity-wall insulation scandal rival PPI?
Excerpts: Many victims' cases were described by the MPs, and all had features in common. One was the way in which the idea of CWI had been presented to them by door-stepping and cold-calling salesmen, describing cavity insulation as being 'Government-backed' or 'Government-funded'. This is not the case. .. Another factor that the victims' cases have in common is the role of the Cavity Insulation Guarantee Agency (CIGA), which issues 25-year guarantees. Salesmen often describe these as 'Government guarantees', which they are not.
Arumala, Joseph O. 'Brick Veneer Steel Stud Wall Systems: State-of-the-Art.' The Masonry Society Journal (2007): 9-19.
Illustrations used in the article above include adaptations from BIA Technical Notes 28B Figure 1 as used in this article. ©IAP 2016
[1] Williams, M.F., Williams B.L., 'Water Intrusion in Barrier and Cavity / Rain Screen Walls', Water in Exterior Building Walls: Problems and Solutions, ASTM STP 1107, Thomas A. Schwartz, Eds., American Society for Testing and Materials, ASHRAE, Philadelphia, 1991, retrieved 8/10/12, Abstract:
Exterior walls are designed and constructed using barrier or cavity / rain screen wall principles. Exterior Insulation and Finish Systems (EIFS) are typically constructed as barrier walls; masonry is often constructed as a cavity wall. These wall systems are discussed along with common deficiencies that allow water intrusion to occur.
[Mark F. Williams and Barbara Lamp Williams are president and vice president respectively of Kenny/Williams/Williams, Inc., a building diagnostics firm at 945 Tennis Ave., Maple Glen PA 19002.]
Airolite BVC Brick Vents (extruded aluminum), The Airolite Company, LLC, PO Box 410, Schofield WI 54476, TelP 715-841-8757.
Brick Development Association, The Building Centre, 26 Store Street, London, WC1E 7BT, England, U.K., Tel: 020 7323 7030, Email: brick@brick.org.uk
Brick Industry Association, 1850 Centennial Park Drive, Suite 301, Reston, VA 20191Phone: 703.620.0010 Fax: 703.620.3928.
Brickvent™, Masonry Innovations, Masonry Innovations, 36 Woodview Drive, Pittsboro, IN 46167, Tel: 317.341.0882 or 317.695.0509, Email: info@masonryinnovations.com - the company provides this BrickVent™ moisture control system instruction sheet. Web Search 02/16/2011, original source: http://masonryinnovations.com/Instruction_Sheet.pdf
Canada Masonry Centre, 360 Superior Blvd., Mississauga ON Canada L5T 2N7. Tel: (905) 564-6622. Offers the CMCA Textbook of Canadian Masonry.
Canada Masonry Centre, 360 Superior Blvd., Mississauga ON Canada L5T 2N7. Tel: (905) 564-6622. Offers the CMCA Textbook of Canadian Masonry. Masonry Design Manual, James E. Amrhein & Walter L. Dickey, Civil & Structural Engineers, Masonry Industry Advancement Committee, Masonry Institute of America, ASIN B0006XMFZE
Tamlyn building products, Tom Tamlyn, President, 13623 Pike Rd., Stafford TX 77477, Tel: 800-334-1676.
'Concrete Slab Finishes and the Use of the F-number System', Matthew Stuart, P.E., S.E., F.ASCE, online course at www.pdhonline.org/courses/s130/s130.htm
Sal Alfano - Editor, Journal of Light Construction*
Thanks to Alan Carson, Carson Dunlop, Associates, Toronto, for technical critique and some of the foundation inspection photographs cited in these articles
Terry Carson - ASHI
Mark Cramer - ASHI
JD Grewell, ASHI
Duncan Hannay - ASHI, P.E. *
Bob Klewitz, M.S.C.E., P.E. - ASHI
Ken Kruger, P.E., AIA - ASHI
Aaron Kuertz aaronk@appliedtechnologies.com, with Applied Technologies regarding polyurethane foam sealant as other foundation crack repair product - 05/30/2007
Bob Peterson, Magnum Piering - 800-771-7437 - FL*
Arlene Puentes, ASHI, October Home Inspections - (845) 216-7833 - Kingston NY
Greg Robi, Magnum Piering - 800-822-7437 - National*
Dave Rathbun, P.E. - Geotech Engineering - 904-622-2424 FL*
Ed Seaquist, P.E., SIE Assoc. - 301-269-1450 - National
Dave Wickersheimer, P.E. R.A. - IL, professor, school of structures division, UIUC - University of Illinois at Urbana-Champaign School of Architecture. Professor Wickersheimer specializes in structural failure investigation and repair for wood and masonry construction. * Mr. Wickersheimer's engineering consulting service can be contacted at HDC Wickersheimer Engineering Services. (3/2010)
*These reviewers have not returned comment 6/95
Masonry structures: The Masonry House, Home Inspection of a Masonry Building & Systems, Stephen Showalter (director, actor), DVD, Quoting:
Movie Guide Experienced home inspectors and new home inspectors alike are sure to learn invaluable tips in this release designed to take viewers step-by-step through the home inspection process. In addition to being the former president of the National Association of Home Inspectors (NAHI), a longstanding member of the NAHI, the American Society of Home Inspectors (ASHI), and the Environmental Standard Organization (IESO), host Stephen Showalter has performed over 8000 building inspections - including environmental assessments. Now, the founder of a national home inspection school and inspection training curriculum shares his extensive experience in the inspection industry with everyday viewers looking to learn more about the process of evaluating homes. Topics covered in this release include: evaluation of masonry walls; detection of spalling from rebar failure; inspection of air conditioning systems; grounds and landscaping; electric systems and panel; plumbing supply and distribution; plumbing fixtures; electric furnaces; appliances; evaluation of electric water heaters; and safety techniques. Jason Buchanan --Jason Buchanan, All Movie Review 
Masonry Design for Engineers and Architects, M. Hatzinikolas, Y. Korany, Canadian Masonry (2005), ISBN-10: 0978006100, ISBN-13: 978-0978006105
Masonry Structures: Behavior and Design, Robert G. Drysdale, Ahmid A. Hamid, Lawrie R. Baker, The Masonry Society; 2nd edition (1999), ISBN-10: 1929081014, ISBN-13: 978-1929081011
Masonry, Engineered: Using the Canadian Code, J. I. Gainville, Cantext publications (1983), ASIN: B0007C37PG
Masonry, Non-reinforced masonry design tables, Hans J. Schultz, National Concrete Producers Association and the Canadian Masonry Contractors Association (1976), ASIN: B0007C2LQM
Moisture Control in Buildings, U.S. Department of Energy
Moisture Control in Walls, U.S. Department of Energy
'Vapor Barriers or Vapor Diffusion Retarders', U.S. DOE: how vapor barriers work, types of vapor diffusion barriers, installing vapor barrier
Ventilation for energy efficient buildings, Purpose, Strategies, etc.,
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & RepairOur recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
Building Failures, Diagnosis & Avoidance, 2d Ed., W.H. Ransom, E.& F. Spon, New York, 1987 ISBN 0-419-14270-3
Building Pathology, Deterioration, Diagnostics, and Intervention, Samuel Y. Harris, P.E., AIA, Esq., ISBN 0-471-33172-4, John Wiley & Sons, 2001 [General building science-DF] ISBN-10: 0471331724ISBN-13: 978-0471331728
Building Pathology: Principles and Practice, David Watt, Wiley-Blackwell; 2 edition (March 7, 2008) ISBN-10: 1405161035 ISBN-13: 978-1405161039
Construction Drawings and Details, Rosemary Kilmer
Diagnosing & Repairing House Structure Problems, Edgar O. Seaquist, McGraw Hill, 1980 ISBN 0-07-056013-7 (obsolete, incomplete, missing most diagnosis steps, but very good reading; out of print but used copies are available at Amazon.com, and reprints are available from some inspection tool suppliers). Ed Seaquist was among the first speakers invited to a series of educational conferences organized by D Friedman for ASHI, the American Society of Home Inspectors, where the topic of inspecting the in-service condition of building structures was first addressed.
Domestic Building Surveys, Andrew R. Williams, Kindle book, Amazon.com
Defects and Deterioration in Buildings: A Practical Guide to the Science and Technology of Material Failure, Barry Richardson, Spon Press; 2d Ed (2001), ISBN-10: 041925210X, ISBN-13: 978-0419252108. Quoting:
A professional reference designed to assist surveyors, engineers, architects and contractors in diagnosing existing problems and avoiding them in new buildings. Fully revised and updated, this edition, in new clearer format, covers developments in building defects, and problems such as sick building syndrome. Well liked for its mixture of theory and practice the new edition will complement Hinks and Cook's student textbook on defects at the practitioner level.
Guide to Domestic Building Surveys, Jack Bower, Butterworth Architecture, London, 1988, ISBN 0-408-50000 X
'Avoiding Foundation Failures,' Robert Marshall, Journal of Light Construction, July, 1996 (Highly recommend this article-DF)
'A Foundation for Unstable Soils,' Harris Hyman, P.E., Journal of Light Construction, May 1995
'Backfilling Basics,' Buck Bartley, Journal of Light Construction, October 1994
'Inspecting Block Foundations,' Donald V. Cohen, P.E., ASHI Reporter, December 1998. This article in turn cites the Fine Homebuilding article noted below.
'When Block Foundations go Bad,' Fine Homebuilding, June/July 1998
Historic Preservation Technology: A Primer, Robert A. Young, Wiley (March 21, 2008)ISBN-10: 0471788368 ISBN-13: 978-0471788362
..
Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: info@carsondunlop.com. The firm provides professional HOME INSPECTION SERVICES and also extensive HOME INSPECTION EDUCATION and home inspection-related PUBLICATIONS. Alan Carson is a past president of ASHI, the American Society of Home Inspectors.
Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' provides extensive home inspection education and report writing material.
The ILLUSTRATED HOME illustrates construction details and building components, a reference for owners & inspectors.
Special Offer: For a 5% discount on any number of copies of the Illustrated Home purchased as a single order Enter INSPECTAILL in the order payment page 'Promo/Redemption' space.
TECHNICAL REFERENCE GUIDE to manufacturer's model and serial number information for heating and cooling equipment, useful for determining the age of heating boilers, furnaces, water heaters is provided by Carson Dunlop Weldon & Associates
Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on any number of copies of the Technical Reference Guide purchased as a single order. Just enter INSPECTATRG in the order payment page 'Promo/Redemption' space.
The HOME REFERENCE BOOK - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume. 
Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page 'Promo/Redemption' space. InspectAPedia.com editor Daniel Friedman is a contributing author.
Or choose the The HOME REFERENCE eBook for PCs, Macs, Kindle, iPad, iPhone, or Android Smart Phones. 
Special Offer: For a 5% discount on any number of copies of the Home Reference eBook purchased as a single order. Enter INSPECTAEHRB in the order payment page 'Promo/Redemption' space.
Building inspection education & report writing systems from Carson, Dunlop & Associates Ltd
COMMERCIAL BUILDING INSPECTION COURSES - protocol ASTM Standard E 2018-08 for Property Condition Assessments
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HOME INSPECTION EDUCATION: HOME STUDY COURSES - ASHI@Home Training 10-course program.
Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on these courses: Enter INSPECTAHITP in the order payment page 'Promo/Redemption' space. InspectAPedia.com editor Daniel Friedman is a contributing author.
The Horizon Software System manages business operations,scheduling, & inspection report writing using Carson Dunlop's knowledge base & color images. The Horizon system runs on always-available cloud-based software for office computers, laptops, tablets, iPad, Android, & other smartphones
Publisher InspectApedia.com - Daniel Friedman (Redirected from Marsden Matting)
RAF aircrew with one of their Bristol Beaufighters on a PSP airstrip at Biferno, Italy, August 1944
332nd Fighter Group pilots discuss combat flying. Walking on Marston matting.
Marston Mat, more properly called pierced (or perforated) steel planking (PSP), is standardized, perforated steel matting material developed by the United States at the Waterways Experiment Station shortly before World War II, primarily for the rapid construction of temporary runways and landing strips (also misspelled as Marsden matting). The nickname came from Marston, North Carolina, adjacent to Camp Mackall airfield where the material was first used.[1]
Description[edit]A section of Marston Mat used to construct the Alexai Point Landing Field in 1943, Attu Island, Alaska, c. 2006
Pierced (pressed, steel planking, named after the manufacturing process) steel planking consisted of steel strips with punched lightening holes in it. These holes were in rows, and a formation of U-shaped channels between the holes. Hooks were formed along one long edge and slots along the other long edge so that adjacent mats could be connected. The short edges were cut straight with no holes or hooks. To achieve lengthwise interlocking, the mats were laid in a staggered pattern.
The hooks were usually held in the slots by a steel clip that filled the part of the slot that is empty when the adjacent sheets are properly engaged. The holes were bent up at their edges so that the beveled edge stiffened the area around the hole. In some mats a T-shaped stake could be driven at intervals through the holes to keep the assembly in place on the ground. Sometimes the sheets were welded together.
A typical later PSP was the M8 landing mat. A single piece weighed about 66 pounds and was 10 ft (3.0 m) long by 15 in (0.38 m) wide. The hole pattern for the sheet was produced to allow easier transportation by aircraft, since it weighed about two-thirds as much. Aluminum plank was referred to as PAP, for perforated aluminum planking,[2] but was and is not as common. Aluminum was a controlled strategic material during World War II, so much less was made; it was typically only able to handle half as many loading cycles as steel, and its high scrap value and short usable life led to recycling rather than reuse.
After the war, PSP was used by many southeastern U.S. auto racing teams, since it was manufactured in the area, and available from many abandoned military airfields. It was also used during a similar period when NASCAR teams used car trailers.
History[edit]World War II[edit]Marshall Slot Drainage Pipe

 As will be explained later, I think the weep openings in the veneer wall shown above, though properly located, are probably not working.
This escape passage and wall design are a method for reducing water intrusion into the structure interior. According to the Masonry Design Manual, weep holes are
Openings placed in mortar joints of facing materials at the level of flashing, to permit the escape of moisture, or openings in retaining walls to permit water to escape.
Above we illustrate the most basic brick wall weep opening.
To diagnose a building water entry or moisture problem originating at its exterior walls we must first understand the construction concepts that were used to build that wall: two very different concepts apply, though they often appear mixed or even confused in buildings: barrier wall construction methods (the wall exterior skin keeps out water) and cavity or rain-screen wall construction (the wall is designed to handle and get rid of water that penetrates the outer skin).
See WALL CONSTRUCTION BARRIER vs CAVITY for definitions and explanations of barrier wall construction compared with cavity / rain screen exterior wall construction methods, objectives, and damage vulnerabilities.
Below we show a brick wall (a veneer in this case) with weep openings at regular intervals at two heights above ground level.
Below is a close up of one of the drainage openings.
Veneer wall weep or drain openings are placed at least at the very bottom of a brick veneer wall cavity and sometimes as vents openings are placed higher in the wall in some designs.
For the wall shown in the photos just above, we suspect that an air space behind the veneer does not extend lower than the weep holes in our photos. Why? The lower wall is solid masonry construction with no air space rather than frame construction. 
The lower brick courses were laid tight, with no cavity at all, against a solid concrete or masonry block foundation wall, thus forming a solid composite masonry wall.
 Typical Construction Specification for Brick Veneer Wall Containing Weep or Drain Openings & Wall Cavity VentsHere are three examples of wall cavity vent and weep opening specifications adapted from the Brick Industry Association (BIA), our industry expert source, and from two example construction specifications for brick veneer walls that offer more details.
Note: the specifications for any particular building project should be made by a qualified design professional such as a licensed professional engineer or licensed architect. 
Weep Hole Wall Vent Construction Specification Example #1 - BIAThe Brick Industry Association recommends veneer wall weep opening specifications as follows:
Weeps:
 Open head joint weeps spaced at no more than 24 in. (610 mm) o.c. recommended
Most building codes permit weeps no less than 3 /16 in. (4.8 mm) diameter and spaced no more than 33 in. (838 mm) o.c.
Wick and tube weep spacing recommended at no more than 16 in. (406 mm) o.c.- BIA 28B cited below.
Above, these weep openings are properly located: above the upper surface of the wall bottom flashing, and they might meet the BIA's 3/16' (4.8mm) diameter, but in my opinion they are inadequate.
At BRICK VENEER WEEPS BLOCKED or MISSING we show that these tiny tubes inserted as veneer wall drains were mostly blocked by mud placed by mud-dauber wasps. Little wall-bottom tubes are also very easily blocked by falling mortar and debris in the wall cavity. Good location, weak weeps.
At BRICK WALL DRAINAGE, FLASHING, VENTILATION PRODUCTS we illustrate a taller, blockage-resistant PVC product that provides better veneer wall drainage opening protection, letting water out while preventing insect intrusion.
Weep Hole Wall Vent Construction Specification Example #2Wall shall use pre-formed control joints using rubber material. Provide with corner and tee accessories and fused joints. 
Weep openings: use molded PVC grilles that are insect resistant, located above-grade and not blockedInstall weeps in veneer walls at 16' (400 mm) on center horizontally above through-wall flashing, above shelf angles and lintels and at bottom of walls
Install cavity vents in veneer walls at 16' (400 mm) on center horizontally below shelf angles and lintels and at top of walls.
Install cavity mortar diverter at base of cavity as recommended by manufacturer to prevent mortar droppings from blocking weep/cavity vents.
Do not permit mortar to drop or accumulate into cavity air space or to plug weep/cavity vents. 
Wall cavity mortar control: Semi-rigid polyethylene or polyester mesh panels, sized to thickness of wall cavity, and designed to prevent mortar droppings from clogging weep openings and cavity vents and designed to allow proper cavity drainage
Venting a Veneer Wall Supported on a FoundationHuuuge casino free chips links twitter. [Click to enlarge any image]
Above: Brick veneer wall construction details showing weep openings immediately above flashing that is in turn atop bottom brick course of a brick veneer wall constructed over a steel stud cavity wall. These details are for a brick veneer wall that rests atop a masonry foundation.
This illustration is adapted from BIA Technical Notes 28B, Figure 1 as used in Arumala 2007 cited below. Critical wall bottom flashing is shown in red, brick veneer weep opening locations above the horizontal portion of that flashing are shown in green, and house-wrap / water barrier fabric(s) are shown in dark gray.
Watch out: Less evident in our sketch but important: the water barrier affixed to the wall sheathing should extend over the top of the wall bottom flashing, not behind it.
Otherwise water in the wall cavity may pass behind the bottom flashing and thus will fail to drain from the wall cavity.
Venting A Veneer Wall Supported by Steel LintelBelow: Brick veneer wall construction details showing the location of weep openings immediately above wall bottom flashing that is in turn immediately above the upper surface of the supporting steel lintel in a lintel-supported brick veneer wall design.
[Click to enlarge any image]
Notice that when the brick veneer is supported by a steel lintel, the weep openings are immediately over the wall bottom flashing that is in turn immediately over the upper surface of the supporting steel lintel. 
This illustration is adapted from Figure 3, 'A Typical Section of a Brick Veneer Wall with Steel Stud Backup Wall' - Arumala (2007)
Weep openings & vents in upper levels of brick veneer wallsAs our photograph above illustrates, in tall brick veneer walls additional weep openings and air vent openings may be specified by the architect/engineer for placement higher in the wall.
Air, Cavity & Weep Hole Wall Vent Specification Example #3Air Vents: Flexible ultra violet resistant polypropylene co-polymer DA1006 Cell Vent by Dur-O-Wal Inc., 7777 Washington Village Dr., Ste. 130, Dayton, OH
45459, (888) 977.9600, www.dur-o-wal.com.Size: Height 2-1/2 inch maximum except as indicated otherwise, by full width of brick.
Color: To match mortar color.
Weep Vents: Flexible ultra violet stable recycled polyester mesh, rectangular shape by Mortar Net USA Ltd, 541 S. Lake St., Gary, IN 46403, (800) 664-6638,
www.mortarnet.com, CavClear Weep Vents by Archovations, Inc., PO Box 241, Hudson, WI 54016, (888) 436-2620, www.cavclear.com.Size: Height 2-1/2 inch maximum except as indicated otherwise, by full width of Brick.
Color: To match mortar color.
Cavity Wall Mortar Net: Lightweight polyethylene, 90 percent open woven mesh by Mortar Net USA Ltd, 541 South Lake Street, Gary, IN 46403, (800) -664-6638,
www.mortarnet.com. or CavClear Masonry Mat by Archovations, Inc., PO Box 241, Hudson, WI 54016, (888) 436-2620, www.cavclear.com.Size: Height 10 inches, thickness as required to fill cavity.
Size: Full height of wall, thickness as required to fill cavity
Weep Holes: Form weep holes in mortar joints of exterior wythe of cavity walls at bottom of cavity over foundations, bond beams, through wall flashings, and other water stops in wall.
 Form weep holes by leaving head joint free and clean of mortar, and raking out bed joint at weep hole.
 Space weep holes approximately 24 inches oc. Keep weep holes free of mortar droppings and other obstructions.
Pointing & Cleaning at End of Wall Construction At completion of masonry Work, fill holes in joints (except weep holes) and tool.
Building Code Requirements for Brick, Stone or other Veneer Wall Drains & VentsU.S. IRC, (2012) International Residential Code, Foundations, R703 Exterior Covering 
Sketch: brick or other masonry veneer wall construction details showing air space, flashing, weep openings, adapted from 2012 IRC cited below. 
[Click to enlarge any image]
R703.1.1 Water Resistance The exterior wall envelope shall be designed and constructed in a manner that prevents the accumulation of water within the wall assembly by providing a water-resistant barrier behind the exterior veneer as required by Section R703.2 and a means of draining to the exterior water that enters the assembly.
Protection against condensation in the exterior wall assembly shall be provided in accordance with Section R702.7 of this code.
Exceptions:
1. A weather-resistant exterior wall envelope shall not be required over concrete or masonry walls designed in accordance with Chapter 6 and flashed according to Section R703.7 or R703.8.
2. Compliance with the requirements for a means of drainage, and the requirements of Sections R703.2 and R703.8, shall not be required for an exterior wall envelope that has been demonstrated to resist wind-driven rain through testing of the exterior wall envelope, including joints, penetrations and intersections with dissimilar materials, in accordance with ASTM E 331 under the following conditions:
2.1. Exterior wall envelope test assemblies shall include at least one opening, one control joint, one wall/eave interface and one wall sill. All tested openings and penetrations shall be representative of the intended end-use configuration.
2.2. Exterior wall envelope test assemblies shall be at least 4 feet by 8 feet (1219 mm by 2438 mm) in size.
2.3. Exterior wall assemblies shall be tested at a minimum differential pressure of 6.24 pounds per square foot (299 Pa).
2.4. Exterior wall envelope assemblies shall be subjected to the minimum test exposure for a minimum of 2 hours.
The exterior wall envelope design shall be considered to resist wind-driven rain where the results of testing indicate that water did not penetrate control joints in the exterior wall envelope, joints at the perimeter of openings penetration or intersections of terminations with dissimilar materials.-
R703.7 Stone and Masonry Veneer, GeneralStone and masonry veneer shall be installed in accordance with this chapter, Table R703.4 and Figure R703.7. 
These veneers installed over a backing of wood or cold-formed steel shall be limited to the first story above-grade plane and shall not exceed 5 inches (127 mm) in thickness. 
See Section R602.10 for wall bracing requirements for masonry veneer for wood-framed construction and Section R603.9.5 for wall bracing requirements for masonry veneer for cold-formed steel construction.
Exceptions:
For all buildings in Seismic Design Categories A, B and C, exterior stone or masonry veneer, as specified in Table R703.7(1), with a backing of wood or steel framing shall be permitted to the height specified in Table R703.7(1) above a noncombustible foundation.
For detached one- or two-family dwellings in Seismic Design Categories D0, D1 and D2, exterior stone or masonry veneer, as specified in Table R703.7(2), with a backing of wood framing shall be permitted to the height specified in Table R703.7(2) above a noncombustible foundation.
Brick Veneer Wall & Curtain Wall Venting & ResearchArumala, Joseph O. 'Brick Veneer Steel Stud Wall Systems: State-of-the-Art.' The Masonry Society Journal (2007): 9-19. Illustrations used in the article above include adaptations from BIA Technical Notes 28B Figure 1 as used in this article. ©IAP 2016
Arumala, J. O. and Brown, R. H., 'Performance Evaluationof Brick Veneer with Steel Stud Backup', Department ofCivil Engineering, Clemson University, Clemson, SouthCarolina, April 1982.
Brick Industry Association, 'Technical Notes on Brick Construction', Brick Industry Association, 1850 Centennial Park DriveSuite 301Reston, Virginia 20191703-620-0010brickinfo@bia.org, Website: www.gobrick.com, retrieved 2016/06/21,original source: http://www.gobrick.com/Technical-Notes Brick Industry Association, [BIA], 'Brick Veneer / Steel Stud Walls, 28B', [PDF] Brick Industry Association, op.cit. (December 2005), retrieved 2016/06/21, original source: http://gobrick.com/Portals/25/docs/Technical%20Notes/TN28B.pdf Excerpt included in the article above
BIA, 'Brick Veneer Construction: Basics of Resisting Water Penetration in Residential Construction', [PDF] Brick Industry Association, op.cit. (Issue 1), retrieved 2016/06/21, original source: http://www.gobrick.com/Portals/25/docs/Publications/Builder%20Notes/Builder_Notes_1.pdf
Excerpt: 
Through-wall flashing is animpermeable membrane placed in thewall that extends from the sheathing,across the air space, and all the wayto the exterior of the brickwork (seeFigure 1). One should place flashingat all points where the air space isclosed off. 
Model building codesrequire flashing at the foundation,above window and door heads, atwindow sills, and where the roof ofa one-story wing meets a two-storybrick veneer wall. 
..
Flashing should extend from theoutside face of the veneer, throughthe thickness of the brick veneer,across the air space to the backing,and then up at least 8 inches. Theflashing should either extend up behind the water-resistant barrieror should be attached to its surfacewith a termination bar. Flashing heldback from the outside of the brickveneer— even just 1/2 inch—couldallow water to re-enter the wall. 
BIA, 'Lo Esencial sobre la Construcción de Revestimiento de Ladrillos y Lista de Control de Trabajo', retrieved 2016/06/21 original source http://www.gobrick.com/Portals/25/docs/Publications/Builder%20Notes/Builder_Notes_Spanish_Issue2.pdf
BIA, 'Brick Masonry Cavity Walls: Introduction,' Technical Notes on Brick Construction No. 21, Rev., Brick Industry association, Reston, VA., 1998.
BIA, 'Brick Veneer/Stud Panel Walls,' Technical Notes on Brick Construction No. 28B, Rev. II, Brick Industry association, Reston, VA., 1999.
Choi, Edmund CC, and Zhihong Wang. 'Study on pressure-equalization of curtain wall systems.' Journal of Wind Engineering and Industrial Aerodynamics 73, no. 3 (1998): 251-266.
Abstract:
In recent years, aluminium-curtain-wall systems are often used in southeast Asia. Many of these curtain-wall systems can be classified as a two-barrier system with a front-panel (the rainscreen) and the back-panel (the air barrier). The back-panels of such systems are usually thin and flexible. 
Compared with the brick or brick-veneer rainscreen walls, where the back-panels are very rigid, the pressure-equalization characteristics are expected to be quite different. To improve on the understanding of the behaviour of such systems and to evaluate design parameters, full-scale measurements were carried out. 
A numerical model which takes into account the flexibility of the back-panel has been developed for the prediction of cavity pressure in curtain walls. The results based on this model show good agreement with those obtained from full-scale experiments.
Drysdale, R.G. and Kluge, A., 'A Summary of Performanceof Brick Veneer/Steel Stud Wall Systems Subject to Temperature,Air Pressure and Vapor Pressure Differential,'Seminar on Brick Veneer Wall Systems, Toronto, Ontario,Canada, June 1989.
ICBO 1997, Uniform Building Code, International Conferenceof Building Officials, Whittier, CA, 1997.
IRC, (2012) International Residential Code, Foundations, Chapter 7, Wall Covering [PDF] 
Keeton, B., 'Prevent Water Intrusion and Minimize Exposureto Claims by Building with Mold in Mind' ConstructionExecutive, vol. 13, No. 7, pg 46-48, Association ofBuilders and Contractors, 4250 North Fairfax Drive, 9thFloor, Arlington, Virginia 22203, June 2004.
Masonry Standards Joint Committee (MSJC), 'BuildingCode Requirements for Masonry Structures', (ACI 530-05/ASCE 5-05/TMS 402-05), American Concrete Institute;Structural Engineering Institute of the American Society ofCivil Engineers; The Masonry Society, Boulder CO, 2005.
McGinley, Mark W., 'An Alternative Design for BrickVeneer Steel Stud Walls', The Masonry Society Journal,The Masonry Society, Vol. 18, Number 2 pp. 9-22, December2000.
Piper, Richard S., and Russell J. Kenney. 'Brick Veneer Walls-Proposed Details to Address Common Air and Water Penetration Problems.' [PDF] In Masonry: Design and Construction, Problems and Repair. ASTM International, 1993., retrieved 2016/06/21, original source: http://www.masonrysociety.org/TMSJournal/Vol.%2025.%20No.%201/P009%202004-10.pdf
Reneckis, Dziugas, James M. LaFave, and Wade M. Clarke. 'Out-of-plane performance of brick veneer walls on wood frame construction.' Engineering structures 26, no. 8 (2004): 1027-1042.
Abstract:
Full-scale brick veneer wall panel specimens, representing typical residential construction practice, were investigated under static and dynamic out-of-plane lateral loading on a shake table. The tests captured the overall performance of the wall system, including interaction and load-sharing between the brick masonry veneer, corrugated sheet metal ties, and wood frame backup. 
The tests evaluated the effects of two different tie installation methods, as well as a veneer-to-backup connection repair using post-installed mechanical anchors. The progression of system damage was noted up until partial collapse of the veneer walls; tie stiffness and strength were found to significantly affect wall performance at all stages of behavior. 
Analytical models for veneer wall systems are being developed based on these experiments to further study the vulnerability of this type of construction.
Straube, J. F., and E. F. P. Burnett. 'Rain control and screened wall systems.' In Proc. 7th Conf. on Building Science and Technology. Durability of Buildings. Design, Maintenance, Codes and Practices. Toronto, pp. 20-21. 1997.
Treshsel, H. R., editor, 'Moisture Control in Buildings',ASTM manual series MNL 18, 1994 American Society forTesting and Materials (ASTM), pp. 224-225, 1994.
Van Straaten, Randy. 'Measurement of ventilation and drying of vinyl siding and brick clad wall assemblies.' (2004).
Abstract: 
Control of moisture and heat flow through building enclosure assemblies is a critical component of overall building performance. This thesis shows that significant drying of moisture in wall assemblies is possible and that ventilation of cladding significantly increases the rate of drying in some assemblies without having detrimental impact on the enclosures thermal performance.
A review found that thermal and moisture buoyancy, wind pressure gradients and mechanical equipment drive ventilation airflow. This ventilation flow can theoretically increase the effective water vapour permeance and thermal conductivity. Ventilation has the potential to increase outward drying through relatively impermeable claddings at the low flows expected to occur in service.
 The impact on thermal conductance is much less. A methodology for assessing the complicated airflow resistance characteristics of lap sidings was developed and applied to a representative vinyl siding. Field drying studies showed that the sample tested is well ventilated. Field brick veneer clad wall samples were also tested for system airflow resistance over a range of driving pressures.
Theoretical predictions under-estimated the measured flow rate for given steady driving air pressures. Measurements of naturally driven cavity air speeds and smoke pencil testing showed that flow rates were commonly occurring that would in theory significantly affect the hygrothermal performance of the walls. This was confirmed with field drying studies. A field drying study of east-facing test wall with vinyl siding and brick veneer cladding was conducted in Waterloo, Ontario, Canada.
Significant amounts of drying and inward moisture redistribution were measured. Wall sheathing dried quickly in hot summer conditions but in some cases significant inward driven moisture flow occurred. In cool and cold weather the wall dried more slowly and much less moisture moved inward. Increased cladding ventilation significantly increased drying rates and reduced internal wall assembly moisture levels.
It was concluded that cladding ventilation acts to increase the effective vapour permeance of cladding and to reduce solar driven inward vapour drives. The use of spun bonded polyolefin sheathing membrane in lieu of #15 asphalt impregnated felt was found to improved hygrothermal performance in the test walls. 
The difference observed was concluded to be due to the higher vapour permeance of the spun bonded polyolefin and may not hold for wall assemblies with lower permeance sheathings (e. g. oriented strand board and foam plastic). Walls clad with vinyl siding dried faster than those clad with brick veneer. It was concluded that the vinyl siding is a well ventilated cladding system.
Williams, Mark F., and Barbara Lamp Williams. 'Water Intrusion in Barrier and Cavity/Rain Screen Walls.' In Water in Exterior Building Walls: Problems and Solutions. ASTM International, 1991.
Also see REFERENCES for this article
Where do the Brick Wall Drainage Openings (Weep holes) Belong?Where do the brick wall weep holes go? This topic has moved to a separate article now found at BRICK VENEER WALL WEEP HOLE LOCATION
Damaged Brick Veneer Walls - Blocked or Missing Brick Veneer Weep OpeningsDetails of this topic are now at BRICK VENEER WEEPS BLOCKED or MISSING.
Not All Brick Veneers Lacking Drainage are Damaged - Some of these are Barrier Walls not Cavity / Rain Screen Walls
Brick Veneer Wall Through-Ventilation - Airflow Removes Moisture?This discussion has moved to BRICK VENEER WALL THROUGH-VENTILATION
Brick Veneer Wall Leakage Problems in Buildings Exposed to FloodingPlease see the new article at BRICK VENEER WALL LEAKS in FLOOD PRONE AREAS
Guide to Brick Wall Drainage Opening, Flashing & Ventilation ProductsMarshalls Slot DrainPlease see BRICK WALL DRAIN, FLASHING, VENT SOURCES
Shown above: A Tamlyn Building Products brick vent screen discussed in the article linked-to just above.

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Technical Reviewers & ReferencesHowell, Jeff, 'Could the cavity-wall insulation scandal rival PPI?', The Telegraph, 16 February 2015, original source: Could the cavity-wall insulation scandal rival PPI?
Excerpts: Many victims' cases were described by the MPs, and all had features in common. One was the way in which the idea of CWI had been presented to them by door-stepping and cold-calling salesmen, describing cavity insulation as being 'Government-backed' or 'Government-funded'. This is not the case. .. Another factor that the victims' cases have in common is the role of the Cavity Insulation Guarantee Agency (CIGA), which issues 25-year guarantees. Salesmen often describe these as 'Government guarantees', which they are not.
Arumala, Joseph O. 'Brick Veneer Steel Stud Wall Systems: State-of-the-Art.' The Masonry Society Journal (2007): 9-19.
Illustrations used in the article above include adaptations from BIA Technical Notes 28B Figure 1 as used in this article. ©IAP 2016
[1] Williams, M.F., Williams B.L., 'Water Intrusion in Barrier and Cavity / Rain Screen Walls', Water in Exterior Building Walls: Problems and Solutions, ASTM STP 1107, Thomas A. Schwartz, Eds., American Society for Testing and Materials, ASHRAE, Philadelphia, 1991, retrieved 8/10/12, Abstract:
Exterior walls are designed and constructed using barrier or cavity / rain screen wall principles. Exterior Insulation and Finish Systems (EIFS) are typically constructed as barrier walls; masonry is often constructed as a cavity wall. These wall systems are discussed along with common deficiencies that allow water intrusion to occur.
[Mark F. Williams and Barbara Lamp Williams are president and vice president respectively of Kenny/Williams/Williams, Inc., a building diagnostics firm at 945 Tennis Ave., Maple Glen PA 19002.]
Airolite BVC Brick Vents (extruded aluminum), The Airolite Company, LLC, PO Box 410, Schofield WI 54476, TelP 715-841-8757.
Brick Development Association, The Building Centre, 26 Store Street, London, WC1E 7BT, England, U.K., Tel: 020 7323 7030, Email: brick@brick.org.uk
Brick Industry Association, 1850 Centennial Park Drive, Suite 301, Reston, VA 20191Phone: 703.620.0010 Fax: 703.620.3928.
Brickvent™, Masonry Innovations, Masonry Innovations, 36 Woodview Drive, Pittsboro, IN 46167, Tel: 317.341.0882 or 317.695.0509, Email: info@masonryinnovations.com - the company provides this BrickVent™ moisture control system instruction sheet. Web Search 02/16/2011, original source: http://masonryinnovations.com/Instruction_Sheet.pdf
Canada Masonry Centre, 360 Superior Blvd., Mississauga ON Canada L5T 2N7. Tel: (905) 564-6622. Offers the CMCA Textbook of Canadian Masonry.
Canada Masonry Centre, 360 Superior Blvd., Mississauga ON Canada L5T 2N7. Tel: (905) 564-6622. Offers the CMCA Textbook of Canadian Masonry. Masonry Design Manual, James E. Amrhein & Walter L. Dickey, Civil & Structural Engineers, Masonry Industry Advancement Committee, Masonry Institute of America, ASIN B0006XMFZE
Tamlyn building products, Tom Tamlyn, President, 13623 Pike Rd., Stafford TX 77477, Tel: 800-334-1676.
'Concrete Slab Finishes and the Use of the F-number System', Matthew Stuart, P.E., S.E., F.ASCE, online course at www.pdhonline.org/courses/s130/s130.htm
Sal Alfano - Editor, Journal of Light Construction*
Thanks to Alan Carson, Carson Dunlop, Associates, Toronto, for technical critique and some of the foundation inspection photographs cited in these articles
Terry Carson - ASHI
Mark Cramer - ASHI
JD Grewell, ASHI
Duncan Hannay - ASHI, P.E. *
Bob Klewitz, M.S.C.E., P.E. - ASHI
Ken Kruger, P.E., AIA - ASHI
Aaron Kuertz aaronk@appliedtechnologies.com, with Applied Technologies regarding polyurethane foam sealant as other foundation crack repair product - 05/30/2007
Bob Peterson, Magnum Piering - 800-771-7437 - FL*
Arlene Puentes, ASHI, October Home Inspections - (845) 216-7833 - Kingston NY
Greg Robi, Magnum Piering - 800-822-7437 - National*
Dave Rathbun, P.E. - Geotech Engineering - 904-622-2424 FL*
Ed Seaquist, P.E., SIE Assoc. - 301-269-1450 - National
Dave Wickersheimer, P.E. R.A. - IL, professor, school of structures division, UIUC - University of Illinois at Urbana-Champaign School of Architecture. Professor Wickersheimer specializes in structural failure investigation and repair for wood and masonry construction. * Mr. Wickersheimer's engineering consulting service can be contacted at HDC Wickersheimer Engineering Services. (3/2010)
*These reviewers have not returned comment 6/95
Masonry structures: The Masonry House, Home Inspection of a Masonry Building & Systems, Stephen Showalter (director, actor), DVD, Quoting:
Movie Guide Experienced home inspectors and new home inspectors alike are sure to learn invaluable tips in this release designed to take viewers step-by-step through the home inspection process. In addition to being the former president of the National Association of Home Inspectors (NAHI), a longstanding member of the NAHI, the American Society of Home Inspectors (ASHI), and the Environmental Standard Organization (IESO), host Stephen Showalter has performed over 8000 building inspections - including environmental assessments. Now, the founder of a national home inspection school and inspection training curriculum shares his extensive experience in the inspection industry with everyday viewers looking to learn more about the process of evaluating homes. Topics covered in this release include: evaluation of masonry walls; detection of spalling from rebar failure; inspection of air conditioning systems; grounds and landscaping; electric systems and panel; plumbing supply and distribution; plumbing fixtures; electric furnaces; appliances; evaluation of electric water heaters; and safety techniques. Jason Buchanan --Jason Buchanan, All Movie Review 
Masonry Design for Engineers and Architects, M. Hatzinikolas, Y. Korany, Canadian Masonry (2005), ISBN-10: 0978006100, ISBN-13: 978-0978006105
Masonry Structures: Behavior and Design, Robert G. Drysdale, Ahmid A. Hamid, Lawrie R. Baker, The Masonry Society; 2nd edition (1999), ISBN-10: 1929081014, ISBN-13: 978-1929081011
Masonry, Engineered: Using the Canadian Code, J. I. Gainville, Cantext publications (1983), ASIN: B0007C37PG
Masonry, Non-reinforced masonry design tables, Hans J. Schultz, National Concrete Producers Association and the Canadian Masonry Contractors Association (1976), ASIN: B0007C2LQM
Moisture Control in Buildings, U.S. Department of Energy
Moisture Control in Walls, U.S. Department of Energy
'Vapor Barriers or Vapor Diffusion Retarders', U.S. DOE: how vapor barriers work, types of vapor diffusion barriers, installing vapor barrier
Ventilation for energy efficient buildings, Purpose, Strategies, etc.,
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & RepairOur recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
Building Failures, Diagnosis & Avoidance, 2d Ed., W.H. Ransom, E.& F. Spon, New York, 1987 ISBN 0-419-14270-3
Building Pathology, Deterioration, Diagnostics, and Intervention, Samuel Y. Harris, P.E., AIA, Esq., ISBN 0-471-33172-4, John Wiley & Sons, 2001 [General building science-DF] ISBN-10: 0471331724ISBN-13: 978-0471331728
Building Pathology: Principles and Practice, David Watt, Wiley-Blackwell; 2 edition (March 7, 2008) ISBN-10: 1405161035 ISBN-13: 978-1405161039
Construction Drawings and Details, Rosemary Kilmer
Diagnosing & Repairing House Structure Problems, Edgar O. Seaquist, McGraw Hill, 1980 ISBN 0-07-056013-7 (obsolete, incomplete, missing most diagnosis steps, but very good reading; out of print but used copies are available at Amazon.com, and reprints are available from some inspection tool suppliers). Ed Seaquist was among the first speakers invited to a series of educational conferences organized by D Friedman for ASHI, the American Society of Home Inspectors, where the topic of inspecting the in-service condition of building structures was first addressed.
Domestic Building Surveys, Andrew R. Williams, Kindle book, Amazon.com
Defects and Deterioration in Buildings: A Practical Guide to the Science and Technology of Material Failure, Barry Richardson, Spon Press; 2d Ed (2001), ISBN-10: 041925210X, ISBN-13: 978-0419252108. Quoting:
A professional reference designed to assist surveyors, engineers, architects and contractors in diagnosing existing problems and avoiding them in new buildings. Fully revised and updated, this edition, in new clearer format, covers developments in building defects, and problems such as sick building syndrome. Well liked for its mixture of theory and practice the new edition will complement Hinks and Cook's student textbook on defects at the practitioner level.
Guide to Domestic Building Surveys, Jack Bower, Butterworth Architecture, London, 1988, ISBN 0-408-50000 X
'Avoiding Foundation Failures,' Robert Marshall, Journal of Light Construction, July, 1996 (Highly recommend this article-DF)
'A Foundation for Unstable Soils,' Harris Hyman, P.E., Journal of Light Construction, May 1995
'Backfilling Basics,' Buck Bartley, Journal of Light Construction, October 1994
'Inspecting Block Foundations,' Donald V. Cohen, P.E., ASHI Reporter, December 1998. This article in turn cites the Fine Homebuilding article noted below.
'When Block Foundations go Bad,' Fine Homebuilding, June/July 1998
Historic Preservation Technology: A Primer, Robert A. Young, Wiley (March 21, 2008)ISBN-10: 0471788368 ISBN-13: 978-0471788362
..
Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: info@carsondunlop.com. The firm provides professional HOME INSPECTION SERVICES and also extensive HOME INSPECTION EDUCATION and home inspection-related PUBLICATIONS. Alan Carson is a past president of ASHI, the American Society of Home Inspectors.
Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' provides extensive home inspection education and report writing material.
The ILLUSTRATED HOME illustrates construction details and building components, a reference for owners & inspectors.
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TECHNICAL REFERENCE GUIDE to manufacturer's model and serial number information for heating and cooling equipment, useful for determining the age of heating boilers, furnaces, water heaters is provided by Carson Dunlop Weldon & Associates
Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on any number of copies of the Technical Reference Guide purchased as a single order. Just enter INSPECTATRG in the order payment page 'Promo/Redemption' space.
The HOME REFERENCE BOOK - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume. 
Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page 'Promo/Redemption' space. InspectAPedia.com editor Daniel Friedman is a contributing author.
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Publisher InspectApedia.com - Daniel Friedman (Redirected from Marsden Matting)
RAF aircrew with one of their Bristol Beaufighters on a PSP airstrip at Biferno, Italy, August 1944
332nd Fighter Group pilots discuss combat flying. Walking on Marston matting.
Marston Mat, more properly called pierced (or perforated) steel planking (PSP), is standardized, perforated steel matting material developed by the United States at the Waterways Experiment Station shortly before World War II, primarily for the rapid construction of temporary runways and landing strips (also misspelled as Marsden matting). The nickname came from Marston, North Carolina, adjacent to Camp Mackall airfield where the material was first used.[1]
Description[edit]A section of Marston Mat used to construct the Alexai Point Landing Field in 1943, Attu Island, Alaska, c. 2006
Pierced (pressed, steel planking, named after the manufacturing process) steel planking consisted of steel strips with punched lightening holes in it. These holes were in rows, and a formation of U-shaped channels between the holes. Hooks were formed along one long edge and slots along the other long edge so that adjacent mats could be connected. The short edges were cut straight with no holes or hooks. To achieve lengthwise interlocking, the mats were laid in a staggered pattern.
The hooks were usually held in the slots by a steel clip that filled the part of the slot that is empty when the adjacent sheets are properly engaged. The holes were bent up at their edges so that the beveled edge stiffened the area around the hole. In some mats a T-shaped stake could be driven at intervals through the holes to keep the assembly in place on the ground. Sometimes the sheets were welded together.
A typical later PSP was the M8 landing mat. A single piece weighed about 66 pounds and was 10 ft (3.0 m) long by 15 in (0.38 m) wide. The hole pattern for the sheet was produced to allow easier transportation by aircraft, since it weighed about two-thirds as much. Aluminum plank was referred to as PAP, for perforated aluminum planking,[2] but was and is not as common. Aluminum was a controlled strategic material during World War II, so much less was made; it was typically only able to handle half as many loading cycles as steel, and its high scrap value and short usable life led to recycling rather than reuse.
After the war, PSP was used by many southeastern U.S. auto racing teams, since it was manufactured in the area, and available from many abandoned military airfields. It was also used during a similar period when NASCAR teams used car trailers.
History[edit]World War II[edit]Marshall Slot Drainage PipeA Curtiss P-40 Warhawk piloted by Squadron Leader Keith 'Bluey' Truscott of No. 76 Squadron RAAF taxiing along Marston Mat at Milne Bay, Papua New Guinea in September 1942
Marston Mat was extensively used during World War II by Army engineers and Seabees (construction battalions) to build runways and other readily usable surfaces over all kinds of terrain. An early in-theater use of PSP was in constructing a 5,000 foot runway on Greenland's 'Bluie West One' (BW-1), an Allied Ferry Command and U.S.A.A.F airfield located on the extreme southwest corner of Greenland, at the termination of Eriksfjord, and near the coastal community of Narsarsuaq. Construction began in early fall 1941, and the first aircraft landed on Jan 24, 1942. Deemed a success, it was then used extensively in the Pacific Theater of Operations. A C-47 Skytrain supply aircraft was the first plane to land on the first steel-mat runway constructed in France after the invasion of Normandy.[3]
On Pacific islands the matting was typically covered with crushed and rolled coral or soil to form a level surface. The perforated and channeled design of the matting created strength and rigidity and facilitated drainage. A runway two hundred feet wide and 5000 feet (1500 m) long could be created within two days by a small team of engineers.
Berlin Airlift[edit]At the start of the Berlin Airlift the runways at Tempelhof Airport in the US Zone of Berlin were made of PSP. Designed to support fighters and smaller cargo aircraft, the Douglas C-54 Skymaster that formed the backbone of the U.S. effort was too heavy for the PSP. Berliners were hired to fix the runway between the three-minute arrivals, running onto the runways with bags of sand to dump onto the mats and soften the surface.
Vietnam era[edit]With the deployment of jet aircraft and helicopters, foreign object damage (FOD) became a larger hazard. In moist tropical areas, such as Vietnam, vegetation growing through the mats also became an issue. Jet blast or rotor downdraft could stir up loose materials on the ground, which might then be sucked into jet inlets, and vegetation required mowing or herbicides. The M8A1 mat was developed to prevent this, omitting the pierced holes that exposed the soil beneath.[4] This mat has a solid surface, strengthened by corrugations that also encouraged the drainage of rainwater. The mat size also changed to be 22 by 144 inches (560 mm × 3,660 mm).
Later mats were developed in a lightweight aluminum version, 24 by 144 inches (610 mm × 3,660 mm).[4] This was made as a hollow extrusion, rather than pressed. Aluminum matting allows greater quantities to be airlifted. Its greater scrap value encourages theft, so steel is preferred for larger or long-term installations.
Landing mats of all types were widely used for construction of bunker roofs and for reinforcing field fortifications, as well as service roads inside fire support bases.
Legacy[edit]Marston Mat repurposed for storage of empty wine bottles on a farm in Normandy in 2007. Hooks and slots along long edges clearly visible
A huge quantity of Marston matting was left in the Philippines by the U.S. forces after World War II. Many of these were re-purposed as fencing material in housing projects that were built after the war. This one, behind the little boy, is located in a housing development in the 1950s that was initially referred to as 'Project One', but later came to be known as Kamuning, Quezon City, near Manila. Photo is dated May 1965.
Free signup bonus no deposit casino usa. Large quantities of matting were produced; approximately 2 million tons costing more than US$200 million (in the 1940s).[5] At the end of the war a large amount of the material remained as war surplus and was pressed into use in various civil engineering applications such as road and bridge construction. As they were made from steel with a high manganese content, the matting was also highly resistant to corrosion.[6] In various countries located in the Pacific Theater, particularly in the Philippines and Papua New Guinea, matting still remains in use as fencing[7] or roadway barriers, in some cases stretching for miles.
Surplus sections of Vietnam War-era mats were used to construct fences along the U.S.-Mexico border in the 1990s.[8]
See also[edit]Sommerfeld Tracking – a form of wire matting
Corduroy road – a road-building method going back to prehistory.
Sedes Airport – an airport in Greece using a PSP Metal Mesh Runway.
References[edit]Wikimedia Commons has media related to Marston Matting.
^Mathis, S. J. (March 1943). 'Mat 'Seabees are Wizards at Building Battle-Front Air Bases'. Aviation Week. 43: 181.
^'Archived copy'. Archived from the original on 2011-06-12. Retrieved 2011-01-06.CS1 maint: archived copy as title (link)
^Gurney, Gene (Major, USAF) (1962). 'The War in the Air: a pictorial history of World War II Air Forces in Combat'. New York City: Bonanza Books: 175. U.S. Air Force photoCite journal requires |journal= (help)
^ ab'Portable Runways Using Landing Mats'. Calumet Industries.
^U.S. Army Corps of Engineers article on Landing Mat DevelopmentArchived 2009-07-24 at the Wayback Machine
^Manganese alloy properties
^Tarawa Photos
^Carcamo, Cindy (9 March 2018). 'Border wall built in 1990s cut illegal immigration, but it also brought problems for small town'. Los Angeles Times. Retrieved 2 June 2018.
External links[edit]Retrieved from 'https://en.wikipedia.org/w/index.php?title=Marston_Mat&oldid=992032695'