Expert: Dave Johnson - 1/27/2008

Question
Howdy... I have a 15' x 20' living room with a stair well to one side. This room has a 20' ceiling. The original home building used this space as a option bonus room above area. I would now like to do this. I would like to know on a 15' run and a 16" center what size 2 by lumber to use, ie. 2x6, 2x8, etc. Also, I will be attaching these studs to vertical 2x4 and 2x6 studs... what do I use to attach them? Do I butt the floor joist studs to the end of the vertical 2x4 studs or do I mount them to the sides of the studs? Thanks so much, Sam

Answer
Hi Sam,
First, 15' is a long span for just dimension lumber. I would use either glue-lams or wood I-joists.

As far as attaching them to the walls, use a 2"x10" "ribbon" flat against the walls lagged into each stud.
Then use joist hangers to attach the new joists to the ribbon (or ledger). Thoroughly nail/screw joist hangers in all holes!

If this doesn't answer your question...mail me...
Dave
I just happened to think, if you are going to have any supporting walls under this floor, you COULD use  dimension lumber. If the wall is in the center, go with
2"x8" @16"o.c.