I recently purchased a 1930's home. It was moved onto the foundation in 1958. I have discovered a section of the foundation that troubles me. The board (do they call this one a floor joist as well?) or whatever that rests around the rest of the foundation is not there for about a 5 to 6 foot section that runs into the corner. There is a rock or a cement chunk in the center of this missing section. Beneath this the wall has a step crack. The step crack is ugly in one spot the block seems like it's turned out and it sticks out almost one inch so there has been some shifting. the top of the wall there is one loose block and a crack that i can see daylight through. I imagine the block is loose because there is know pressure on it. All the pressure is on the concrete chunk. I have no water leakage in hard rains but it must be damp anyway because the dehumidfier likes to run for then rest. The bad section is near the floor drain. I have a deck off the back of the house where this section is and there is a tree built around in the corner of the deck it is around 10 ft away from the house. It is a large old tree that towers higher than my 1 1/2 story house. I'm guessing roots could cause alot of pressure. I'm gonna take the **** tree out anyway. The rest of the foundation is within a 1/2 or less of being plum and alot of it is plum. there is a thin step crack under a window and on the bad wall there is another small step crack about 15 feet away. I'd really like to prevent any other **** from happenin. I'm new to this my first home, i'm young and dumb. Any advice would be great.

From your description, it appears that you have a full basement with a concrete floor. You have described step cracks and referred to a a loose block, which indicate that the exterior wall of the foundation is made of concrete block. Is that correct? Are there any intermediate supports to the first floor joists and beams? Perhaps block or brick pillars, or steel posts? Do they rest on foundation pads, or just on the concrete floor?

It is unclear what kind of rim support you are talking about. I have seen, in an older house, an eight-by-eight creosote beam laid along the foundation wall to act as rim joist. In more modern construction, dressed lumber, 2x4 or maybe 2x6 is anchored along the length of the foundation wall. To the outside edge of the 2x lumber, a 2x8 or 2x10 or 2x12 is attached edge on. The ends of the floor joists are then placed at right angles to the rim joist and bear on the exposed face of the 2x sill plate, then are nailed through the rim joist to hold them in place. It sounds like you are missing a part of the rim and/or sill.

What do your floor joists rest upon in this section? The foundation wall? A support beam? What is the concrete chunk supporting? Is it supporting a beam or other structural member?

I am confused by your description of the crack your are most concerned with. You said ". . . there is a loose block and a crack that I can see daylight through." Is the wall containing that crack below ground, or can you truly see daylight through it? If the wall is above ground, that has a direct bearing on what may be going on. Please clarify.

The presence of the tree and proximity of the floor drain may also have some influence on the problem. For instance, is the drain an active drain receiving some kind of discharge fluid on a regular basis, such as A/C condensate or sump pump discharge or some such?