I want to replace the stair treads and risers leading to my second floor. These stairs were manufactured in 2010. The treads are routed into the side stringer/skirt. There aren't any additional stringers running underneath the treads themselves. I can cut out the original treads but the problem is supporting the new treads since I wouldn't be able to embed them 1/2" on both sides, like the original treads are. After I remove the original treads, can I nail pieces of 2x4 into the stringer/skirt flush with the bottom of the routed out section in order to support the new treads? I can then nail the new treads in using 2" 18 gauge nails. The new treads are 1" thick oak and I plan on staining them after I install them. Any thoughts/comments on this approach are appreciated.

I’m building a 20 x 30’ detached garage that has 12’ long 2 x 6” stud walls. I believe the subcontractor took the 12’ long 2 x 6’s as delivered, built the walls and then sheathed the exterior with 4 x 8 OSB sheets. I’ve since noticed that the studs in about half of the wall are bowed out to the side. So much so that halfway up the wall some of the spacing is up to 1.5” wider or narrower then at the bottom of the wall. Is this an issue? I know the sheathing will keep the studs in place to some extend but I have know idea if that is enough. I haven’t asked the contractor about it yet but would like to have a few other opinions before I have his response. I haven’t tried to measure to see how consistent the wall height is across the whole wall length. Should I? thanks