I am in the beginning stages of finishing my basement and need advice on attaching walls to floor joists.
The short of this question is: What is the best way to do this? Is nailing directly into the bottom of a joist a good idea?

The long is: my floors measure 101" to 101 1/2....my studs measure 96" and with two plates that will end up measuring 100". At this point I'm planning on using 2x4 to shim the top of the wall....nail the shim into the bottom of the joist and then nailing the top plate of the wall frame to the shim...Good idea? Do I want a "float" or "gap" between my top plate and the floor joist above?

Thanks,

Jamie

 

If you have the space on the floor, lay the two plates & the studs in position & build the wall on the floor. It can be done is sections, if necessary. Then flip it up into the vertical position & use some pieces of 2x4 to nail or screw it to the joists every 3 feet or so.

 

I have read elsewhere that if you are on clay that heaving of the floors can be an issue. So you want to leave a gap at the top of your wall. Not sure if this is the case, just sharing info.

 

If your studs are 96", two plates will only get you to 99", not 100". I like Pulpo's idea. Go with two bottom plates, the first one being pressure treated. But with 3 plates, your max wall height is only 100.5" You still have 1" to 1.5" to make up. That'll be a pretty thick shim. I guess you could go with 2 headers, 2 footers, then trim your studs to fit. That might be cheaper than exchanging all of your 8'ers for 10'ers.