help with flooring problem

Old 01-19-09, 11:09 AM
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help with flooring problem

my wife and i bought our 10-year-old home 3 years ago..we paid for a home inspection that found some relatively minor problems - all seemingly unrelated moisture damage..those problems were fixed prior to purchase.

since then, an ever-increasing list of moisture-related flooring problems has appeared..i'm in marine construction and am generally home only one week/month, hence we have not closely or continuously monitored problems until they were glaring..initially, we had a spot in the laundry room, surrounding the floor vent, that got "spongy"..i "corrected" it myself by simply scabbing a section of treated 3/4" plywood under the spongy area and it corrected the sponginess..

however, in studying the problem and what could be done i found that the entire crawl space and insulation, floor joists, and subflooring above it were wet and many places had mold growing on the wood surfaces..we have very clayey surface soils here and my suspicion is that lack of any percolation traps water underneath..the previous owner was obviously aware of the problem because they installed ventilation fans underneath and covered the entire crawl space with rolled polyethylene..i should also mention that the floor "joists" are actually composite chipped plyboard..two thin sheets of that obs(?) board with a 1x1 edge, top and is essentially a constructed wood i-beam, with a narrow web (1/2" thickness/8" depth) and flange (1")..i know little about house construction, but i've never seen such floor joists.

anyway, we now have spongy spots all over the house, particularly in spots where you stand (or sit) for periods of front of lavatories, kitchen sink, all toilets and laundry room..unless i discover we have some miraculous legal recourse, i'm gonna have to try and correct the problems myself..i don't even know whether i should pull up the flooring and subflooring and approach it from the top, oe repeat my last correction and scab over the spongy spots from the bottom..realizing, of course that until i resolve the underlying moisture problem, everything is a band-aid..

i really need suggestions..even suggested reading materials to help me better understand the problem would be appreciated..thanks.
Old 01-19-09, 03:02 PM
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What you are describing are a product called by one manufacturer Trus Joist I beams. They are one of the strongest flooring members you can buy if installed properly. You can span upwards to 26' without center support. How tall are the joists, and is there any large holes cut across them, say for air conditioning ductwork or plumbing. That will definitely weaken the I beam and is specifically prohibited in the installation process. Did your inspector note the poly covering on the soil in the crawl space? If not, the PO probably just installed it, and the damages were already on their way when they did it. Having the poly on the soil is a correct measure to keep the moisture from infiltrating and attaching itself to the joisting. I am not sure what your subflooring is made of, but my guess it is particle board, and that is unacceptable, as it will deteriorate with moisture. When you made your attempt to correct the sponginess, what was the condition of the subflooring? You gotta get the moisture stopped first, then attack the method of repair, which may very well entail removing the subflooring and replacing with a better product.

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