First, I am new to this site so please be nice and redirect me to the correct place if necessary.
My house was built in 1942. I have lived here for just over a year with no real concerns. Currently I have ripped off the vinyl siding only to reveal the original clap board siding which was in very bad condition and is now gone as well. However I have discovered that the sill, I believe this is the correct term for it, has an area approximately 8 feet in length directly below the bay window which has had some significant water and probable but not current termite damage to it. The clap board was so rotten it fell off the house when I tapped it with the hammer. I have read a few threads regarding replacement of this section and I would just like someone to clarify a few points for me please.
The beam is 10"x4". Is it ok to replace it with 2, 10"x2" boards, and if so should I brace them together before I fit them into place and what is the best way do this (hurricane brace, screws, nails, ect.) Can I replace the entire section in one piece or should I do two 4' sections. Exactly how do I secure these boards to the brick foundation as I cannont tell upon examination how or where the other parts of this beam are secured to it.
I have placed some support boards under the horizontal 2x4 for support of the wall, but it should be noted that there is no sag in the wall, window or flooring on the exterior of the home or on the interior of the home. So is it ok to leave these here while I replace the sill or do I need additional support elsewhere. I am planning on moving the supports to the 2x4 directly under the window sill afterwards in order to replace that particular 2x4 that they are resting under right now(see photo). Is it ok to support the wall in this place as well.
The subflooring directly above the sill is rotted as well, but it should be noted that underneath, in the crawl space there is no rotting of the floor joists, also noted that the floor joist do not sit on this beam for support they are notched out and sit directly on the brick foundation and butt up against the beam perpendicularly. Do and Can I replace this section of the subfloor from under the crawl space without disturbing the flooring inside the house (as it is the original hardwood floor!), and how far back should I make the cut? The flooring from the crawlspace going up in layers looks like: 1x10's running diagonally across the floor joists ( the outer 4 inches of which is rotted) then a thin layer of plywood? not rotten. Then some other layer which does not seem to be affected either.
I have attached a picture for your viewing pleasure. I would appreciate any advice you can give me.