I posted this under Foundations, but thought I should ask here as well. I just bought a 1850's antebellum home, and need some help with one of my rooms.

In one section of the house, under what is one of the two living rooms, we have old termite damage, in some areas going all the way through the original hard wood floors. This is spotty, and can be fixed with about 10-15 planks, but my question / problem involves the floor joist.

Under this room, just outside the perimeter, I have huge 12x12 beams boxing in an area of approx 20 feet by 15 feet, placed upon large CMU's, and according to my inspector, appear unaffected by the termites, then notched into the beams, I have six floor joists which measure 4 inches x 61/2 inches by 19 feet. One joist has almost been entirely destroyed by the little vermin, with the other five showing very minimal damage.

My question is, should I just look at replacing the on one bad joist, and sandwich the others with bolted 2x8's cut to fit, or since there is some sagging of all the beams running 19+ feet which is requiring bracing at the 9' mark, should I pull all six of the beams, and install engineered joist running across the short side of the box, or perpendicular to what they are now? Would sandwiching them and jacking up solve the sag with out having to add a cross brace midway across? There is plenty of room for hangers, so that is not a problem, and either way seems about the same amount of work, so which way do I receive the most benefit?

On such a structural issue, I do not even consider the "original classic" issue, besides the old owners already added vinyl siding, windows and drywall, so to worry about that seems moot. They are really cool beams though, where you can see the hand carved marks for notching them into the larger beams, as if Norm himself did them!

I am not asking for final determination, just various ideas. Thanks for your help, sorry I rambled on

Craig