Hi,

Im looking to install either 3/4 prefinished hardwood or engineered floors. I just pulled up all the particle board after a carpet was removed. Underneath the particle board is a tongue and groove plank that is at least 1 1/8 inches thick. It is pretty flat. What do I need to put between that and the new floor? Should I lay down some CDX plywood? Do I need to put felt paper or another type of moisture barrier? Also, should I put down a moisture barrier under the house in the crawl space?

Thanks for all the help! Plus throw down some of your favorite prefinished/engineered brands if you have the time.

Yes, and yes......15# asphalt under the hardwood, 6-8 mil poly in the crawlspace....whatever you do, don't ignore the crawlspace....make sure you have adequate cross-ventilation as well. As far as the subfloor, thickness-wise, you are ok. Make sure of the flatness, and make sure they are secured well to the joists. If so, you are safe to lay the hardwood at a 90 degree angle to the plank subfloor. If you can't run it at a 90 degree angle, add 3/8 or 1/2" plywood, then your asphalt paper, then the hardwood.

As BW says, the single most important aspect of prepping your site for new hardwood is a close examination of the crawlspace, and drainage around the foundation. While we dont have much crawlspace construction in our area, I fully understand the value of isolating ground dampness from the interior of the house.