19. In a building without a moisture protection system, 80% of its internal moisture originates from building site ground water. HUD Research Paper #28
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21. Table 2 Drying Time to reach 3.0 lbs/1000 sq ft / 24 hrs Water-Cement Ratio Bottom Sealed Bottom Exposed to Bottom In Contact Water Vapor with Water 0.40 46 52 54 0.50 82 144 199 0.60 117 365 >>365 0.70 130 >>365 >>365 0.80 148 >>365 >>365 0.90 166 >>365 >>365 1.00 190 >>365 >>365 4 inch thick specimen dried at 73 o F and 50% relative humidity
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24. Due to excessive moisture and a high pH in the concrete surface, the adhesive under this vinyl backed carpet tile has re-emulsified and lost most of its holding strength. Moisture Related Flooring Problems
26. Figure 3-6 - Residential carpeting contaminated by the mold Stachybotrys Atra can cause severe allergic and toxic reactions. (Photo courtesy of Floor Seal Technology, Inc.) Moisture Related Flooring Problems
28. Alkali has infected this vinyl flooring, causing the yellow discoloration in this medical facility’s floor. The bottom portion of this photo shows older concrete flooring that has a lower pH; it is not discolored. Moisture Related Flooring Problems
29. A living room floor shows a heavy concentration of sulfate salts on the slab. Water from outside garden sprinklers breeched the exterior walls. When the water evaporated, salts were deposited – this attracted moisture and led to mold growth in the carpet and backing. Moisture Related Flooring Problems
30. Rubber floor tiles placed over a floor made with lightweight aggregate concrete bubbled after several months in service Moisture Related Flooring Problems
31. Standing water is visible under this vinyl-backed carpet tile on a concrete slab-on-grade floor. Moisture Related Flooring Problems:
32. Carpet tiles curl and de-bond in a large commercial cafeteria, due to infiltrating rain, creating a tripping hazard at an emergency exit. Moisture Related Flooring Problems:
33. How to Prevent Moisture Infiltration Not all waterproof materials are vapor-proof, but all vapor-barrier materials are inherently waterproof. Type of Infiltration Preventative Measure Hydrostatic Pressure Proper site drainage or drainage layer Waterproof barrier Capillary Action Capillary break layer (drainage layer) Waterproof barrier Vapor Pressure Vapor retarder
34. Detailing around pipe banks can be best accomplished using granular sodium bentonite. This is how not to detail a pipe bank.
51. Standard Test Method for Peel or Stripping Strength of Adhesive Bonds Test Results - ASTM D 903-98(2004) Testing performed by TSI on 10/14/04, Test Report # 28444 Specimen Peak Load – lb/in Type of Failure 1 6.89 Peel/Strip 2 6.13 Peel/Strip 3 13.84 Peel/Strip 4 6.51 Peel/Strip 5 10.22 Peel/Strip 6 10.43 Peel/Strip 7 8.07 Peel/Strip 8 8.25 Peel/Strip 9 6.80 Peel/Strip 10 6.88 Peel/Strip 11 4.97 Peel/Strip Avg. 8.09 Peel/Strip
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57. Self adhering sheet membrane waterproofing adhered to the ground is probably not good waterproofing or vapor retarder system.
58. Properties for Specified Performance Classes (ASTM E 1745) * Tensile strength per unit width for the total sample thickness is used instead of tensile strength per unit area because vapor retarder materials are never used in unit thickness. Class A Class B Class C US Units SI Units US Units SI Units US Units SI Units Water Vapor Permeance 0.3 perms 0.3 perms 0.3 perms (E154, Section 7 or F 1249), max (0.3 gr/[h/ft 2/ in./Hg]) (17 ng[(s/m2/Pa]) (0.3 gr/[h/ft 2/ in./Hg]) (17 ng[(s/m2/Pa]) (0.3 gr/[h/ft 2/ in./Hg]) (17 ng[(s/m2/Pa]) Tensile Strength (E 154, Section 9), * min 45.0 lbf/in. 7.9 kN/m 30.0 lbf/in. 5.3 kN/m 13.6 lbf/in. 2.4 kN/m Puncture Resistance (D 1709, Mehod B, min) No inch-pound equivalent used 2200 g No inch-pound equivalent used 1700 g No inch-pound equivalent used 475 g
Inteplast Group, the largest plastics extruder and resin producer in the world is the manufacturer of the Barrier Bac product line. Barrier Bac is a 12 year old product line has been the fastest growing vapor retarder in the United States for the past 4 years. The entire Barrier Bac product line is manufactured in the United States with 100% US resins and labor.
My name is Dave Zill. A graduate of the University of Tennessee (Geology), I have spent my career in the geotechnical engineering and construction business.
These are the 2 reason you’d typically use a vapor barrier – slab on grade, beneath conditioned space OR slab on grade under moisture sensitive flooring. This is essentially the most important information to take away from this presentation.
Table of values used in HUD Research Paper #28. This technical research is one of the most referenced in the industry.
Based on the data provided in the previous slide, as a concrete slab dries and cures, nearly 12 gallons of moisture is released by the slab every 24 hours for every 1000 SF of slab.
It’s expensive to condition a space. The HVAC system in your project is typically designed to condition the space by removing humidity.
The ground water in reference is on-site moisture – by definition, soil is 100% humid. Water vapor travels from areas of high humidity to areas of lower humidity. With a “dehumidifier” running above the slab, the HVAC system “pulls” water vapor from below the slab and into the building, thus forcing itself to run longer and more expensively. A vapor retarder will effectively shut off the water vapor entering from the building site.
A typical water-cement ratio would be ~ .50. Here, three scenarios are presented: Bottom in Contact with Water (Concrete is placed directly on wet ground) Bottom exposed to water vapor (concrete placed on bare soil with no visible moisture – but remember soil is, by definition 100% humid) Bottom Sealed – (Concrete place vapor retarder)
The latest avenue for pipe bank sealing is the place granular sodium bentonite around the penetrations and simply saturate with a water. It works and it is quicker and easier than tape and mastic.
These are the current codes for vapor retarders.
There’s really no reason to use anything but a Class A vapor retarder.
This chart is from the American Concrete Institute (ACI). Please note, ACI has recently changed it’s stance on Figure 3. Due to the relatively large risk of water (irrigation, rain, etc…) filling the space below the slab and the vapor barrier acting as a bathtub, ACI recommends Figure 3 ONLY when the building site is totally in the dry (shell built) and the slab and granular material are fully encapsulated on all sides.
Example of a cross laminted LDPE membrane being installed.
Cross laminated membrane installation. Note the number of hazards on this jobsite. Will your vapor retarder survive construction?
Again, constructability and proper installation is key.
On the slab on grade, notice the vapor retarder has pulled away from the concrete. This is called “pocketing” and is caused by settling of the building pad or granular materials. ACI clearly states the vapor retarder should remain in direct contact with the concrete at all times. Pocketing is common and nearly impossible to prevent, thus peal adhesion (how well does the vapor retarder “stick” to the concrete is critical. Some may say hydrostatic pressure will “push” the vapor barrier upward, but the nonlinear nature of this pressure over a building site would make this virtually impossible.
It is important to understand that cross laminated LDPE samples provide, on average, more than 8 lbs of peel adhesion. Remember ACI recommends constant constant contact with the slab – Do you know the peel adhesion of your current vapor retarder?
There are many composite vapor retarders on the market as well. Many are used for expansive soils, very high dollar floor ($25 / SF and up), and very heavy slabs.
The added strength of the geotextile on this cross laminted LDPE membrane allows for greater constructability, peel adhesion, and a higher coefficient of friction providing for improved safety.
This inspector is showing the geotextile on a cross laminated LDPE composite vapor retarder is placed to receive the concrete (black side up in other words).
Leed description.
Geogrid reinforced Segmental Wall and slope technology can earn credits under Sustainability of sites, energy and atmosphere, materials and resources, and innovation and design, out of the 69 points available.
Leed requires submittal of the design concept for points in this category.
