I told my contractor that I wanted a 6'8" high pony wall to extend 10 feet out from the side wall into my living room so I'd have a place to hang my TV. He said "You can't do that. A wall that high would be all floppy. You have to attach it to the ceiling." I didn't want to attach it to the ceiling and I didn't think it had to be floppy, plus the contractor used the wrong pronoun. (he should have said "I" not "You").
I wanted a wall that looked like this (only finished).
First thing I did was cut back the carpet and saw out a section of the floor to expose three of the bays between the floor joists.
I cut a 2x10 and screwed&glued it to the floor joists. I bolted&glued the 2x4 that would be the end stud to the 2x10, cut four 2x4 blocks to fill the space between the 2x4 and the floor joists and screwed and glued them in place. Then I bolted the floor joists together with 7/16 all thread. I put a length of 2X6 under the flooring as far back under the new wall as I could get it working through the hole (about 4 feet) and screwed&glued it to the bottom of the flooring.
I built the rest of the frame for the wall and set it in place. I nailed it to the end stud and put a 2x6 gusset in the upper corner. I glued the bottom plate to the floor and put screws through into the 2x6 I had put under the floor.
I was having such a good time hanging drywall that almost forgot the blocking to hang the TV from.
The wall is up. It doesn't exactly ring like a tuning fork, but it's tight and I can lean my 230 lbs on it at about a 30% angle and it doesn't budge. Now I just have to do the finish drywall work, which I hate. I'd hire someone to finish it, but they'd probably tell me it can't be done because I'm making 1/2 radius rounded corners on it.
