Architecture - Stress Cracks

I live in a 1956 house in Chula Vista CA. I've heard many times the ground is "unstable" around here. Anyway, I've lived here since 1998, I've always had stress cracks around doors and windows, but lately it seems to be getting worse. I have doors where the lock side has dropped as much as 1/2", (or the header has raised, I don't know) this is amazing to me seeing how we're talking about a 30" space. Also, it doesn't seem to happen in just one direction. If the walls run east to west or north to south, the doors are getting severely out of whack. The house has a crawl space with a perimeter foundation and pier blocks supporting the entire inside of the house. There are no foundation walls under the house, even under load bearing walls.
Anyway I would appreciate it if someone could take a little time and give me your input. You've probably seen this before and know what's causing it. I'd like to see if there's anything I could do. I thought about maybe putting a few shear walls on the interior of the house or beefing up the foundation.

Thanks,
Brian

The amount of movement you describe is not just some minor shrinkage or settlement.

I would suggest you contact a structural engineer to look at your house and explain what is happening. He could also give you some general options on repairs. It could be that there has been some settlement that could be remedied by sjscking and shimming.

A professional opinion would eliminate the guessing and he would not be selling a construction project that he would be doing.

Dick

As Dick said, you definetly need to contack a structural engineer. I have repaired many homes like your, and each one is different. The area that you live in is a somewhat unstable area. Good Luck

I thought I said that.

Jack even heard me.

Dick