We're building a new deck, and yesterday I removed the old ledger board from the old deck and to my horor, discovered that for years, water had been seeping between this board and the rim joist on the house, and the rim joist is now badly rotted. In fact, there's about a 12-18" section that is all but not there now, once I poked many holes through it with my finger...
So now I need to know how to go about replacing it, so I can continue on with the deck. I've googled for info without much luck. The little info I found via google assumes that the rim joist is perpendicular to the floor joists, and that it's right over the foundation. In my case, it's parallel to the floor joists (and on the gable end of the house), and since it's a split-entry house, there is a short (approx 5') wall between this joist and the block foundation below.
My questions are:
a) do I have to replace this joist as a complete span, or can I cut it out and replace the damaged chunk? The posts dealing with the joists right over the foundation imply you can just cut out the damaged section, but since I'm over a wall, I wasn't sure if this was more structural. For what it's worth, the wall's top plate is only a single 2x4, not a doubled header plate like you'd expect if it were load bearing.
b) What, if anything, do I need to do to brace the house temporarilly during this repair? As I have vinyl siding over "build rite", I can get to the framing reasonably easy from the outside, but both levels of the inside are finished and would be a major problem to remove anything down to the framing members. The damaged chunk isn't doing anything structurally now, but I want to make sure I don't have "the walls tumble down" if I remove a slightly bigger one...
Any advice is greatly appreciated. I"d like to (at least start to) tackle this project today, so any info I can get ASAP would be wonderful.
-Tim
P.S. By the way, I'm pretty handy with repairs and with a hammer -- just never had to tackle anything of this nature before (and hopefully won't anytime soon after this!