So I am renovating a cottage and the 2×6 joists – below the new Dinning Room, which used to be a Bedroom, after is was originally a Porch – which span 9′-8″ are spaced 5′-6″ on center with 2 x 6 bridging or secondaries every 24″. The decking is 5/4 x 3 1/4 T&G fir. The concensus is the floor bounces a bit too much and needs to be beefed up.
So I rip up the decking and discover that the main house structure does not have a rim joist to attach my new ledger board to. What I have instead is as follows:
1. There is no rim joist.
2. The mud sill ( a single 2 x 4, on the flat) edge is flush with the foundation wall exterior.
3. The existing joists of the house end flush with the mud sill/ foundation wall exterior.
4. There is 2 x 4 bringing 6″ away from the end of the joists.
5. The existing joists of the house are 2 x 8s 16″ oc.
6. The top edge of the 2 x 8 joists are exposed by about 4 1/2″, meaning they are not sheathed.
7. The new floor is below where the studs are, since they, as usual, sit above the joists and on top of their own bottom plate and on top of the decking.
8. The old ledger board was a 2 x 4 attached to a 1 x 6 T&G bead board. Both were nailed into the endgrain of the house joists!
My first knee jerk reaction was to figure out how to frame a rim joist/ ledger board assembly to the existing joists of the house. But then took a giant step back and thought of the following:
Tie the new joists in with the existing joists, using 2 x 8s sistered to the old joists resting on the existing mud sill, and continue to the opposite wall. Then my only question would be: By how long would the new joists need to overlap the existing joists – beyond the mud sill? I could notch around the 2 x 4 bridging, but would they have to extend that deep?
I would then install 2 x 8 blocking between the joist assemblies.
Any other ideas?
Frankie
Edited 5/4/2004 7:09 pm ET by Frankie