Could I ask a silly question. What does VDR stand for?
I am closing in a car port and putting hard woods over a concrete slab, and I want to be sure I get the vpaor barrier right.
Thanks.
Could I ask a silly question. What does VDR stand for?
I am closing in a car port and putting hard woods over a concrete slab, and I want to be sure I get the vpaor barrier right.
Thanks.
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Replies
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I am about to do a remodel of a strapped wood floor over a concrete slab, should the concrete slab be covered in poly to prevent moisture from rising up into to the wood sub floor, is moisture a concern, the room is at ground level and is heated year round.
*Uh-oh ... yes moisture is a concern. I'll be listening in...
*Absolutely ... without a doubt ...since the houses's humidity level is affectd by the upward migration of ground moisture through the slab more than any other factor (unless you have a swimming pool in the house). There are some recently advertised and newly patented concrete sealers that might work -- check the archives in the concrete section of the AEC info site.Use a Hilti or other hit gun to embed pressure treated firring strips and caulk under the poly or other VDR material across the tops of the firring strips. Lay a line of caulking along the full length of the firring strips (under the VDR) so your staples (or other flooring fasteners) will not compromise the seal when they penetrate through the VDR, poly and into the base. Use a VDR of a materila that will stand up to the beating of the finished floor's installation. The VDR will prevent the toxic off-gasing from the pressure treated firring strips from entering the living space. Make sure the VDR perimeter seal is tight. Basically, your objecive should be to isolate the unheated and non-waterproofed concrete mass from the house. It sucks off heat and transports moisture. If the climate is cold, you can used 2X's for firring strips and lay in some EPS or XPS styrofoam insulation between them. If you seal-tape the joints, the foam will serve as the VDR except where the firring strips bridge the concrete to the floor. I would still use a VDR.
Could I ask a silly question. What does VDR stand for?
I am closing in a car port and putting hard woods over a concrete slab, and I want to be sure I get the vpaor barrier right.
Thanks.
Vapor Diffusion Retarder
check out http://hvac.bobvila.com/Article/744.html
Hey, Huck. Thanks.
The problem I'm having now is finding a place that sells the VDRs. Any suggestions?
I think any building supply house would have Tyvek or similar. (edited to add: I forgot that your concern was sealing concrete - Tyvek obviously not the likely choice there. Try a concrete paint or sealer that is compatible with the glue you're using - if in fact you are using glue to install your flooring! I have installed Armstrong interlocking composite (wood-look) flooring that requires a pad underneath, which I'm sure acts as a VDR, since they specify that it be sealed at the seams with vinyl tape) See below quote from the U.S. Dept. of Energy website
"Types of Vapor Diffusion Retarders
"Vapor diffusion retarders (VDRs) are typically available as membranes or coatings. Membranes are generally thin, flexible materials, but also include thicker sheet materials sometimes termed "structural" vapor diffusion retarders. Materials such as rigid insulation, reinforced plastics, aluminum, and stainless steel are relatively resistant to water vapor diffusion. These types of vapor diffusion retarders are usually mechanically fastened and the sealed at the joints.
"Thinner membrane types of VDRs come in rolls or as integral parts of building materials. A common example of this is aluminum- or paper-faced fiberglass roll insulation. Foil-backed wallboard is another type commonly used. Polyethylene, a plastic sheet material, can be used as a VDR for above grade walls and ceilings (only) in very cold climates (in locations with 8000 Heating Degree Days or higher).
"Most paint-like coatings also retard vapor diffusion. While it was once believed that only coatings with low perm ratings (see below) constituted the only effective VDR, it is now believed that any paint or coating is effective at restricting most water vapor diffusion in milder climates.
Edited 2/22/2005 12:33 am ET by Huck