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.