Q: My new guest house had to have the floor entirely replaced three months after completion as it was badly cupped. My builder found a conduit that was cracked and leaking water into the house and covered all costs. Now the floor is entirely cupped again and he is willing to replace again but admits that he does not know what is causing it.
He recommends that I go to tile this time. I want wood! But, even with tile, won’t the moisture that is causing the cupping harm the subfloor and foundation? What can I do?
A: When there is a moisture issue the problem needs to be corrected first. Part of this also means making sure the wood structure the floor is sitting on is also dry and stable. Did the builder test everything with a moisture meter before proceeding? If this water was soaking dirt in a crawl space, was this all dried and vented and a tarp placed over the damp ground to impede moisture? Has anyone put a moisture meter on your wood floor to check readings? Normal would be 7-9% in most cases. If you get readings 15% or higher, you will have problems. If you are in a cold climate as I am, you could go through a heating season and see how the floor reacts and whether it gets worse or better and when you get normal readings on all structures and the floor have it sanded and finished or stained accordingly. And if you have an ongoing moisture issue under the sub floor I wouldn’t think this would be a good thing for the joists, etc. The moisture has to go some place.