A question about floor joists

If you want to do a bang up job and cure all your problems then do this. First use a support beam that you can jack up to take the load and sag out of the floor. You want to put this an inch or two to the side of the existing joist. Next cut out the existing joist and then use a saws all to cut the flooring nails off flush with the sub-floor. Next install a new joist in the original position insuring that it is at the proper height with steel shims. It wouldn't hurt to toenail the joist at the ends and maybe put a brace block to the next joist over. Then lower the temporary support so the floor rests on the new joist. Job is done and never to be worried about again unless the termites come back.

Jack