I Currently have Old school 2 1/2” x 8” floor joist 16”oc spanning 13’6” and also have 2×8 Doug fir Spanning 11’6”, also has 1×4 nailed on subfloor. There are 1×4 X cross bracing already in place. I am currently renovating and have a chance to stiffen up my somewhat bouncy floor. I know cutting the spans in half with a beam works but in my case I don’t wanna lose the head height in the basement and would have to run posts and new footings in the basement for 55ft.
What would be the best option to stiffen up the floor.
1. Doubling all the floor joist with new 2×8 and replace the 1×4’s with ¾ Advantech glued and screwed.
2. Leave it as is with all single 2×8’s and just Replace 1×4 Board subfloor with 1 ⅛” advantech glued and screwed
3. Rip it all out and go with 2×10 and 3/4 advantech.
1. Doubling all the floor joist with new 2×8 and replace the 1×4’s with ¾ Advantech glued and screwed.
2. Leave it as is with all single 2×8’s and just Replace 1×4 Board subfloor with 1 ⅛” advantech glued and screwed
3. Rip it all out and go with 2×10 and 3/4 advantech.
Ripping it all out would add alot of extra work, cost considerably more for lumber labor and garbage removal.
Assuming 40dead 10 live L/360
#2 Douglas Fir.
Replies
I don’t think the subfloor ing options will get you as much improvement as additional joists. Could a.so try mid span blocking that’s usually very cost effective for a start; but then you couldn’t go back and add joists. So just from incremental sequencing, I’d double up joists, then mid span blocks, thicker subfloor. Your depth is the ‘killer’ ;2x10 would have greatest impact but you lose 2 inches headroom.