Acceptable to hear moisture barrier under flooring?
Lisa G
7 years ago
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Joel Leber
7 years agoLisa G
7 years agoRelated Discussions
Glue down engineered on slab--moisture barrier needed?
Comments (6)Atelier is right on the money as far as moisture testing is concerned and it is best to slab test on or right after high humidity and rainy days to get the worst-case-scenario test returns. The flooring system integrity will only be as good as it is in its worst day in the enviroment its installed in. After you get test results and compare them to the manufacturers product tolerances, then you can decide on the right product for that application or other remedies to bring it to withing manufacturer tolerances. The key here is prevention. Guessing isnt knowing, and any preventative measures used by guessing might be overkill OR might not be enough for the product. You just dont know without testing and in some cases an area will never be good enough for some products without rectifying the underlying construction causing the problem. Yes, some adhesives and substrate treatments will add a water vapor barrier and stop or stem hydrostatic pressure in the substrate but they all have cap limits. Owens Wood Flooring has a comptehensive information section of their site on Owens Plankfloor Gluedown Installation Owens states the following: "MAKE CERTAIN BUILDING INTERIOR AND SUBFLOOR ARE DRY Interior walls should be dry enough to be painted and a room temperature as required by adhesive manufacturer with a relative humidity of 30-50% should be provided before any installation begins. To determine if a concrete slab is suitable for hardwood flooring, please follow the NWFA guidelines to perform a Calcium Chloride test. If excessive moisture is present, do not lay flooring. Check floor in several locations. Concrete sub floors must be clean, flat and sound and of sufficient compression strength (3000lbs PSI) being sure that the surface is not slick. Sections not flat such as waviness, trowel marks, etc. are to be eliminated by grinding or the use of an acceptable leveling compound. Especially along the walls, the sub floor flatness must be checked and, if necessary, improved. Flat to 1/8" in an 8 radius. In addition to concrete sub floors, these products can be installed over dry, flat wood sub floors, such as plywood. If plywood is used as an overlay over an existing sub floor, the thickness of the overlay material much be such as to yield a total ¾" sub floor thickness. New wood type sub floors should also be checked for moisture using a moisture meter. In general, wood or plywood sub floors should not exceed 12% moisture content or 4% moisture content difference between wood flooring and sub floor." The NWFA is a resource you can only get information from if you are a paying member, so you might want to search around for the same information on calcium chloride tests from a independent source if you or your installer isnt a member. It should be noted that there are different types of moisture testing. 1. Relative Humidity of the Installation Area. 2. Moisture in the substrate itself hydrostatic Pressure. 3. Moisture testing the wood looring itself before the install to ensure its equalized to the within-tolerance installation area humidity. Here is some more information you may find useful: moisture testing hardwood flooring moisture testing for relative humidity in a room hydrostatic pressure in concrete ASTM F2170 ASTM F1869 your installer should be well educated in all of the above. ask them plenty of questions and get a good comfort level in their abilities. ask for and check out their references too....See MoreMoisture barrier? And use it under plywood below cabinets?
Comments (5)Floortech, do you mean to tell me that you didn't take notes last time I asked questions on the Flooring forum (three pages ago by now)? Just joking. I'm sorry that I did not provide the full context. The area that we are laying the laminate down includes one room with plywood subfloor and two rooms just with fir "hardwood" planks. Underneath is a crawl space. We got the Costco Harmonics Laminate floor. It's 5/16" thick and comes with a 1/16" foam backing. On the installation instructions, it says "Harmonics flooring with underlayment already attached to the flooring panel requires the use of a moisture barrier (included int he Harmonics Installation kit) over concrete subfloors and is recommended over wooden subfloors." Now that I just typed out the sentence, it dawned on me that it's not saying the moisture barrier is recommended for the wooden subfloors; rather, it says the panels with foam backing are recommended for wooden subfloors. But the customer service rep I talked to also told me that moisture barrier is recommended (not required) for wooden subfloors. Did we both get the grammar wrong? Anyhow, dear Floortech, what would you do if you were to install our floor, esp. with the plywood under the cabinets. We just hope to have a solution that can provide the maximum warmth and comfort (but cork flooring is out of our budget right now)....See MoreRecs for Moisture Barrier and flooring on Concrete Slab
Comments (2)Funny you posted this today ! I was just meeting with a man for my new home flooring and we discussed the moisture level in slabs. I too am on a slab and he suggestes that I have a test done before we determine the appropriate flooring. He did tell me there is a moisture barrier that can be put down (sorry, I can't remember what he called it) he did say it was expensive around $3.00 sq. ft....See MoreAnyone prefer not using moisture/vapor barrier under wood floor?
Comments (1)Moisture barriers and vapor barriers are NOT the same thing. Moisture barriers are intended to stop the movement of liquid water. Vapor barriers are intended to slow the movement of water vapor. The bottom of wood floors is not normally finished so a barrier is used to try and slow the annual movement of water vapor in and out of the wood so it more closely matches the movement through the finished top surface. This helps control changes in shape and size of the strips, but cannot stop it completely. Chapter 3, Physical Properties and Moisture Relations of Wood from the Wood Handbook (USDA) is linked below. Figure 3-3, p. 8 shows how all wood changes shape and size as the moisture content varies. Here is a link that might be useful: Wood Handbook, Chapter 3...See MoreCancork Floor Inc.
7 years agoJoel Leber
7 years agolast modified: 7 years agom_gabriel
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