I'm building a 1.5 story cabin and have a full perimeter 8" block foundation that's 20' x 40' with 16" x 16" piers inside…2 rows of 5ea piers. Piers are the same elevation as the perimeter block.
My joists will run with the 20' width, 3 joists to create the 20' span (sill plate to pier…pier to pier…pier to sill plate). Basically 3 joist 6.6' long.
My questions are…
Can I run a sill plate from pier to pier the 40' way, for the girder (for lack of better definition) to sit on, and use that sill plate as a ledger for the joists? Didn't know if the ledger would have to be nailed to the sides of the girder.
Secondly, will I need to double or triple the girders.
I plan to use 2 x 8's for everything.
This is the way I had planned to frame it.
,
but the piers are actually 16" x 16" rather than 8" x 16".
Best Answer
No. Your joists must bear on the beam directly, using hangers or actually resting on it. Even if you'd bolt the ledger up to the bottom of the beam you'd be relying on cross-grain strength. Not a good situation.
As to your beam sizing question, that's for an engineer to answer (with drawings in hand). We don't have enough information about the structure as a whole to properly answer that. I can speculate, since 2x8 lumber isn't used for floor systems anymore, that even tripled you wouldn't meet most codes.