Problem with underlayment for hardwood floor

[CBGumby]

We bought a log home that was built in 1982. We tore out the carpet in the dining room to install 3/4" rescued walnut hardwood flooring.

What was underneath the carpet is what looks like particleboard. The room is 14' x 14'. There is a dip in the middle of the subfloor. It is probably about 9/16" at the deepest dip, my husband just measured.

How do we correct this? Tearing out the subfloor and replacing it is not an option, and self-leveling compound won't work, as we can't nail hardwood floor into it. I also didn't want to do self-leveling compound, then put plywood over it, because as it is, the hardwood is going to be higher than the floors in the adjoining rooms.

I read somewhere about using asphalt shingles. Is this a good idea? What do you all suggest we do?

thanks!

[Tandy Reeves]

If taking out the partical board is not an option, then choose another floor covering. You cannot nail to partical board. It has no holding power. The sag in the floor should be checked to see why it is sagging. The sag may indicate you have other problems that may include the floor joists, and their supports. Asphalt shingles will work, but you are adding more weight to an area that is already sagging.

[Onyx Hardwood]

I agree with Tandy. You should also check to see if the subfloor is buckling between the floor joists. You have no option but to replace the subfloor. The particleboard just will not hold any type of nail or staple down application. But on the lighter side it may mean that there is nothing wrong with the joists but the particleboard itself. I have heard of people replacing the particle board with OSB (3/4") as well and they say it will work. I don't know myself because I've never done it. But many builders have gone to OSB due to it being cheaper. May check with an "Honest" local flooring contractor to see what they recomend.

[TFP Admin]

After all the trouble I went to to give you a nice avatar, don't break the rules you said you wouldn't when you joined. This topic is over 3 years old. Start a new topic about the same issues, if you want to be helpful.

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TFP Admin