Re: squeak between joists and into wall
I had a similar situation in my house a few years ago (built in 2003). It was caused by the floor flexing under the sole plate of the wall, and a nail from the sole plate to the floor moving in and out when you walk by. The floor joists were not the culprit. The quick and dirty solution was to drive a shim between the wall and subfloor to take up the slack and prevent the movement. If you have access to the subfloor from below (crawl space or basement) you might try driving some screws up into the sole plate. That would tie the subfloor to the sole plate and prevent the movement that causes the squeak.
The "Senior Member" designation under my name doesn't mean I know a lot, it just means I talk a lot.I've been a DIYer since I was 12 (thanks, Dad!). I have read several books on various home improvement topics. I do not have any current code books I can refer to. I was an apprentice plumber for two years.