Hi,
My house was reported built in the 40s. It has a rubble foundation. There are 6 or 7 3"x8" joists running from the front of the house to the back resting, apparently, directly on the top of the foundation. I can see no sill. Running perpendicularly across the middle of the basement, through notches in the foundation is a 6"x8" beam, on which the joists also rest.

Below the middle of the beam is a half timber, under each end of the beam is a steel jack post. The jack have been raised to the point that the half timber in the middle is just barely touching the beam. Both ends of the beam are nearly rotted off. None of the visible part of the joists appear to have rot, they all appear dry and sound except that one has been cut off to make space for the basement stairwell on one side of the basement. A joist in the middle has been cut off to make space for duct work running into the crawlspace of an attached 2 story shed style addition which has other problems.

Neither me nor the house inspector I hired when I bought the house 3 years ago noticed the condition of the beam.

Can the beam be replaced? or, can additional beams be put in to handle the load? What's the ballpark cost of such an undertaking? What kind of contractor do I call?

I'm in the process of selling the house.

Thank you.