Hi all...first post:

Since poly sheeting is inexpensive, is there any reason(s) not to put it down before laying #15 roofing paper as a precaution for a bamboo install over a crawl space? I have poly sheeting on the ground in the crawl space, but with very heavy rains, water can migrate(mostly sub-surface thru clay) under the house.

Thanks,

Pete

The position the NWFA and NOFMA take is that polyethylene should not be layed over a wood subfloor. The reasoning is that the poly film will trap any moisture vapor eminating from below and could cause premature rot. While it may help to protect the floor covering from moisture migration, it may also lead to damage to the subfloor by not allowing that moisture migration. Best to not do it and re-grade around the house to divert surface water away from the house. Or install drainage.

Thanks for the reply, unfortunately, the flooring has already been purchased. Last year, I had new poly installed, along with extra venting in the crawlspace. Right now, it appears to be dry, and definately has very good ventilation. My main concern is one corner of the house where the grading was poorly done. I will check the humidity level underneath the house and proceed from there.

PS I'm currently trying to find an Aquabar dealer that isn't a 2 hour drive. Would this be a good compromise, all things considered?

Me again , would a moisture tester like the one linked below be useful in checking the current state of my subflooring?

http://cgi.ebay.com/Digital-Moisture-Meter-Wood-Veneer-4Pin-5-40-Tester_W0QQitemZ220015375398QQihZ012QQcategoryZ4678QQrdZ1QQcmdZViewItem

thanks,

Pete

Yes that will work. I did notice a +/- accuracy of 1%, the professional models are dead on accurate.

Vented crawlspaces invite moist air. If you want to use plastic, staple it to your framing from underneath. It is a monstrous pain in the rear, but it definitely works.