Floor Joists. Do they still do it this way?
My late 1940's 3-family (30'x34') has 2 8x10 beams (below the 1st floor) in the center of the house running the from the front of the house to the back, with about a 5' gap between them (the space between the beams is basically the front stairways and rear stairways on each floor, and continues all the way up to a 6' wide center dormer on the 3rd floor. The joists are all 2x8's, which are 12" on center. Under each wall (most run parallel to joists) are double joists and even triple joists in some places. The joists are notched out to "hang" on the beams, and then a 2x4 is nailed to each side of the beam to add additional support for the joists to rest on. Above the beams are bricks with mortar (I'm guessing this is a fire stop so it won't enter wall cavities?) This is also done along the two sides of the house, but the front and back just have these rim joists, as far as I can see.
Also, the walls around the front and back stairwells have double layers of what looks like 3/8" drywall. This is even applied to the ceiling (bottom of staircase above) of the stairway as you walk down the basement stairs. (Stairs are stacked)
I've never seen a house before where joists were 12" OC, also, I've never seen the whole brick and mortar thing. Is this commonplace, am I a lucky guy who has an overbuilt house, or is it necessary to hold up three floors of house?