An update -- I removed more of the siding/sheathing, and along with lots of
water damage from the damaged area all the way to the foundation, I found
that the short wall actually **is** a double top plate, so I am now much
more comfortable in thinking this is a load-bearing wall. It was so rotted
out that I thought the second board was a nailer for the inside finishing
surfaces, but is indeed supposed to be two 2x4 top plates.

One additional complication -- if I were to replace the joist all the way to
the corner, this would require removing all siding on BOTH sides of the
corner, as the corner piece (not sure what it's called) is attached under
the siding, and this would have to be removed. Yuck.

My current theory is (much of this borrowed from an article in the Feb/Mar
2002 Fine Homebuilding, which I found this morning at the library):

1) bolt a temporary 2x10 above the patio door (after removing some siding)
using 2 1/2" lag screws per stud.
2) Rent a couple of sufficient (10 ton?) jacks to ease the load on the
members
3) Cut out the damaged joist and top plate (approx 4-6' section, depending
on how much I cut out)
4) Add significant new supports between concrete foundation and new members
6) Let the jacks down and put all the siding back.

Does this sound like a reasonable solution? Is there anything special I
need to do to keep the repaired joists from twisting under the loads (both
from the house and from the new deck? I only have access from the
outside...

-Tim

"Tim Fischer" wrote in message
...
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 a

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!