So I have a 2x10 floor joist that's only about 5 feet long (short because it only spans a rounded part of my house) which has termite damage at one end for about 1.5 feet. The damage is on the outward side of the joist making it much thinner than 2" once the damaged bits are flaked off. The end sits on a notched sill on the curved wall on the masonry since I have brick exterior walls. The notched sill area is not wide enough to have 2 sistered joists rest on it. It is the first joist and doesn't really seem to have much weight or load on it since the load is mostly on the exterior brick wall at that spot.
If I were to do this myself - would I cut out the affected end by a few feet and replace it with a partial new joist which I sister to the old joist, or should I just replace the entire joist since it's only 5 feet long in its entirety?
I am assuming that I can't just sister it the whole length since the edge of the sister can't sit on a sill?
The joist goes in front of the hvac register so I shouldn't have to cut any duct, just maybe hold it up if the register edge is screwed into the joist.
Images below and I drew a blue line in the floor plan of where the beam is along with the red line indicating the termite damage. Note that the white residue on the wood is from the BoraCare termite salt that was sprayed on - the wood is normally a nice brown.
In case anyone is interested, I ended up have 2x8s bolted/sistered together to replace what turned out to be an actual 3x8. I used some shims on top of the brick sil.
To get it in, broke the concrete cap in the notch, put in the double beam, and then re-cemented it back in.