I will be having the floor of our crawlspace filled with concrete soon.

However, about a year ago I installed 3/4" x 3 1/2" solid prefinished T&G maple flooring in the room directly above the crawlspace. The floor sits on 1 1/4 inch of subflooring and 15# felt.

Any recommendations as to how to minimize cupping/buckling and any other ill-effects that the moisture from the curing concrete may potentially cause?

Attach a moisture barrier to the underside of the floor joists, is about all I can recommend. Then it would be just like the moisture barrier placed over a slab, before screeds are placed.

Thanks. I figured that was what I would have to do.

I was hoping that someone was going to tell me that I don't need to worry about it.

Oh, you need to worry about it alright!

Yeah. I know. I was just hoping against hope.

I'll probably staple plastic sheeting up on the floor joists above. Do you think that would do it?

You may need some batting, in stratigic places to hold up the moisture barrier.

Just staples only, seem to poke holes, that tend to rip/pull holes in the plastic.

Thanks for the help.

Well, we had the basement done. I had a discussion with the owner of the business and the install guys and they all said not to worry about the vapor barrier on the ceiling of the crawl. They said they've done tons of homes with solid wood floors above and they've never had a problem.

I told them my concerns and the reasons for them. They in turn came back and said that the barrier couldn't be made air tight and therefore, there would be moisture that would accumulate on top of the plastic. That, they said, would be worse than nothing at all.

At any rate, I went ahead and let them install without the barrier. It should be interesting to see what happens over the next few days.

Keep us posted.

All finished and no problems. We had concrete poured into the crawlspace of a little over 600 sf. About an average of 4" thick concrete over gravel was poured.

I put a small dehumidifier down there in the hopes that it would help. I don't know if it did, but we had no issues with the floor above. It was only about 200 sf of flooring anyway, so I wasn't too terribly worried. But, I'm glad it went without a hitch.