On Jun 26, 5:44 pm, mistersulu wrote:
Hi all:

I'm attempting to replace a section of my kitchen floor all the way
down to the crawlspace (which does get very wet at times) that was
badly damaged (termites and water leak). The subfloor consisted of:
1" tar-covered particle board, diagonally set 1x8s, and 1" plywood. I
intend to place a pre-finished hardwood layer on top of the fixed
floor.

Now, I can easily replace the 1x8s and the top layer of plywood, but
the tar-covered particle board was probably put down in 1942 when the
house was built and doesn't seem to be used any more. My question is,
1) What should I use to replace this board and the 1" space and psuedo-
vapor barrier that it represented, and 2) does a "vapor barrier" over
1/2 of the kitchen sub-floor make any difference? Or should I just
put down 1" of good plywood directly on the floor beams.

Thanks in advance for the help.

Here's the thing:
You stated that your crawl space gets really wet at times. The problem
with wet crawl spaces is,
- They cause mold growth in every organic surface, and that includes
wooden floor joists, sub floors and some types of insulation.
- They harbor moisture loving pests, such as termites (and if did
detect some termite damage too right?)
-They ruin your indoor air quality and are a burden when it comes to
heating and cooling costs.

So, without solving the moisture problem in your crawl space, no
matter what you do in terms of vapor barrier in your kitchen floor, it
will not keep the moisture from the crawl space from rotting anything
that is underneath the vapor barrier. Does it make sense? So it is not
even a matter of "if" you are going to do this kitchen floor
replacement again, it is only a matter of when... And if it the crawl
space gets wet as you say it does, it will be sooner than you'd like
to think.

My recommendation is that you control moisture in the crawl space, by
encapsulating and conditioning it. And you will not need to worry
about placing any vapor barriers on your sub floors.
There are a ton of independent studies about the benefits of crawl
space encapsulation. You cane see some of them he
http://www.crawlspace.org

Here you can find some more information and alternatives:
http://www.basementsystems.com/learn...er/crawlspace/