Hidden from view inside it’s metal box, a radiator in my apartment developed a slow, dripping leak. I only discovered the problem after my downstairs neighbor said he was getting drips from his ceiling. The situation is now under control and will soon be repaired permanently.
My problem is that water crept between the bottom of my hardwood floorboards and the top of the subfooring. Three or four floorboards have begun to cup (warp such that a cross-section would appear slightly U-shaped) for a run of about 6 feet.
Will this problem correct itself as the wood dries out? If not, is it somehow reversible? If not, is my only solution to sand the peaks flat?
Thanks all in advance.
Well, I’m not sure of the logistics of the situation from your description, but if the boards are still wet, dry them with a heavy object on them - for instance, get a couple of 2X6s, place them over the warping boards, and stack books or free weights or something on them - this will let the boards dry straighter, rather than curvier.
They’ll never go back by themselves. The water may cause even more to come up if it’s still between floors. The moisture needs to be removed as soon as possible. The damage will continue to progress as long as the water is between the floors. The floor may only need to be sanded down and resealed, but you might need to replace some floor boards.
Chances are that the boards might warp even worse as they dry.
As this is an apartment, and assuming the leak is not your fault, the landlord / building owner should fix this. Fixing a warped floor is a few steps beyond being a nice tenant and fixing minor things like a loose doorknob or worn sink faucet washer.
My guess is that the fibers in the bottom of the boards have soaked up water and expanded. If they are given the chance to dry up, especially with weight applied they could settle back down. If you sand the peaks before the wood has dried completely you could end up with valleys as the wood reverts. Depending on how much of a cup has developed you may have loosened the nails the floor is fastened with. At this point you will need someone with floor experience, I am just an amateur woodworker.
Wood will move back, case in point: I was sanding a walnut table top, about 18" by 42". Thinking I was coming back the next day I kept it on the bench. When I returned to the shop a week later the top was cupped about 1/2". I flipped it over, clamped it flat and waited a couple of days. Now it is flat again.