Last year I had a pier & beam addition put on my home in Houston, Texas. A vapor barrier was not placed over the soil, insulation was placed between the joists and the perimeter has been sealed with cement board. The joists are approximately a foot off the soil and the structure is heated and airconditioned. During the winter the structure is very damp and musty smelling. I was just before having vents placed in the cement board when I read Bruce Hurley’s recommendatins in Q&A in the September, ’04 issue of Fine Homebuilding. What with our high humidity here I realize that I may be wise to follow his recommendations. Only the subfloor has been installed and if necessary I could remove it and proceed to seal the area as Hurley recommends. If this space is sealed as suggested, will it be necessary to instal a/c ductwork to the crawlspace? There is no plumbing beneath this structure. Any suggestions will be greatly appreciated.
Mike
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"when I read Bruce Hurley's recommendatins in Q&A in the September, '04 issue "
Might be better if you tell us exactly what the recommendations were in case some of us don't have that issue right handy... It sounds like you are talking about a sealed crawl space.
However, regardless of what you do, you need to get some black 6 mil poly (or similar) on the floor of the crawl space covering the soil. Sounds like it could be very difficult in your situation, but without the vapor barrier on the ground ALL bets are off.
Also, you need to be sure that the area surrounding the addition is properly graded so that there is no way that water is gonna run under the addition. Thirdly, if you have gutters and downspouts, be sure that the downspout water is piped away from the foundation.
If you do decide to proceed with a true sealed crawl space, you will need a small HVAC duct down there which essentially ensures air movement - but this is entirely hinged on your getting the crawl space bone dry first. Otherwise, you will be forcing more damp, musty, possibly moldy air up from the crawl space into the living space. :-(
BTW - is radon much of an issue where you live?
I'd call the contractor back ASAP, and try to get him to deal with the "damp and musty smelling" environment on his dime... Then go from there. If he is an upstanding kind of guy, he will at least come back and look at the situation. If he is a low bid kind of guy, he won't.
Harley recommended installation of a vapor barrier, sealing then using a spray-in foam on the walls.
Thanks for your feedback, I was beginning to realize that I was going to have to take the floor up, just glad to have some confirmation. The drainage system is excellent on the structure and radon is not a factor here. I was quite pleased with the construction other than this problem so I will call the contractor and get his input also.
Mike