I have an install to do in 1 month. We're installing 2 1/4" x 3/4" select quarter-sawn white oak (solid) right over the existing old flooring which is
3/4" diagonal pine planks as subfloor and 3/8" (thick) x 2" wide oak (not typical 2 1/4") on top of the pine sub-floor. It's over a 2 foot crawl space and it's our monsoon season with alot of rain here in Arizona. Monsoons have about quit for the season.
House is 100 years old.
My initial reading of the old oak floor is 9-10%. RH is 50% at 76 degrees. Customer does have air conditioning, but it hasn't been running for past two weeks.
Question: Does the moisture barrier have to be in the crawl space or can I trowel on a vapor barrier or lay 6 mil thick ON THE OLD OAK before putting the felt down? OR since I get these readings in the wettest months of the year, can I just depend on the stability of the quarter-sawn and not worry about a vapor barrier?
OR am I playing with fire by not applying NWFA procedures? (I know what you purists would say! ha, ha)
Thanks in advance.
Charlie

A wood and plastic sandwich will make a fine place for rot and mold to form. hire the neighborhood handyman if you dont want to crawl around on your belly. sure qtr sawwn floor is stable but I would shoot for that 9 10 percent mark on the flooring itself if possible. The floor may crack a little in late winter but I would rather have that vs a swollen cupped floor.

Mold Charlie.... It is the asbesto's of the new millineum. I would cover the crawl space, and watch to see if the inside changes. I have been covering crawl spaces of late, and seen quite a drop in subfloor mc. I assume you'll be doing one of your fine sand and finish's on it?? You know you are within spec now,(ASSuming, the oak is at 6) but maybe you could use Perry's finish nail trick to check the mc down deeper? Covering the crawl space is money.

SK:
Thanks. I have a month that I can play around with this thing. First off, I want to make sure there is venting. Also, they have air conditioning. So, I want to make sure that it's not venting down under the house.
Appreciate everyone's input into this. Trying to get a feel for this wood floor thing and make a little . . . no, ALOT of money out here in Arizona.
I've been in business here less than a year after moving from Pennsylvania and I'm booked out into October. Never been this busy in my life.
Charlie

Thats awesome, Charllie, I'm happy for you. I'm familar with you from your posts here and at Flooormasters.. Ohers may disagree, but finishing is far more diffficult then installling. Deal with the mositure thing, and you are on your way. Arizona is pretty dry and I would think one of the easier places to install in, as far as climate goes.
I sure do miss Delta Tech....