I removed the carpet and padding to clean some cat urine smell so it was really the perfect time to fix all these squeaks. The house was built in 1976 and I can’t think of a room without a squeak, small or large. With good quality constructions, builders nail and glue subfloors on joist to help prevent squeaks. This was not done this way in my house.
Squeaks are caused by movement in wood seams between sheets of subflooring. It is basically wood rubbing on wood. Stop the movement and you stop squeak. Most of the time, it is easy to silence these squeaks if you know a few tricks.
First of all, some will advise lubricating the squeaky area with talc or graphite powder. Well, this will silence the squeak for some time and it will come back like a bad rash. I prefer to go for a more definitive solution: prevent the rubbing.
My squeaky floor is over a finished basement so I’ll attack from above. It is easier when you can access the floor from below. The first thing we need to do is find a squeak. I like to have a systematic approach to make sure I fix all squeaks. After all, it is not every day that you remove the carpet and get to work directly on the underlayment and it would be really annoying to do all the work to stretch the carpet back in place only to notice that you forgot to silence another squeak!
I usually walk where the floor is nailed to the joist, following the joists. I use the tip of my fott to put some pressure around existing nails. It takes a little experimentation at the beginning but I have found this technique very effective once you get used to it. I suggest you start looking for squeaks in areas where people usually walk a lot. Boards located immediately under walls are much less likely to squeaks beacuse they have not been exposed to repeated walking as much as boards in the middle of the room. For instance you can probably find a squeak by walking the closest path from the entrance of the bedroom to the window.
When a squeak is found, you can silence it by nailing the board on the joist with an 6d or 8d rign haul nail or driving a 1 1/4 drywal screw. I prefer using screws because I beleive they do not pop as easily as nails. Do not forget to drill a pilot hole.
After you have fixed all squeaks or movements, I suggest you do not put the carpet immediately and wait for a few days. If you live in a climate where humidity can dramatically change, it is a good diea to test the floor a second time on a very humid day (or very dry depending on when you did the first fix), just to be sure you did not miss anything.