Here is a rough sketch and some pictures. The house is about 70ft long so the ends are cut off in the sketch.
The house is 1962. The slab portion is about 4' off the ground and was supported by a 4" block wall around the perimeter and 2 columns. I have had additional support of double 8" blocks (16") columns every 4' (21 of them) after an outer footing was found broken.
I believe there was a wall at the beam but not sure because it is inside the brick house. However this could be wrong. There is another porch that is now a sun room. I plan on removing the glass room and making it just a porch.
The peak of the house roof runs parallel to the Fireplace and the beam in the middle. About where the word WoodFloor is.
I do know that everything on the inside of the beam is 3/8" wall board and old lumber and everything from the slab to the outer brick is 1/2 wallboard, bead board and new dementional lumber. I think the changes were done in the 70's That was also when the attached garage was made into the Master BR.
I have since replaced the bead board with wall board.