We live in a small (1,500 square foot), one-floor, old (most of it 65 years old, some of it 30) house just south of San Francisco. We've lived here about 25 years and the last few years we have heard a lot of popping noises in the ceiling and walls.
It's been getting worse and worse. Some we hear in the early morning. Some we hear when we walk on the floor near structural walls. We can see some unevenness in a wooden floor and a few hairline cracks in the wall and ceiling too.
My initial thought is that we are having problems with a sinking foundation. Maybe too much water near the foundation in the rainy season. But I don't really know.
What kind of inspector or contractor should I contact to evaluate this? How best could I find someone?
UPDATE: I might add that we sometimes get noises also from a hot water pipe under the house. And that we have a crawl space that is hard to access. I have not been under there for 18 months, but last time I was there I didn't see anything unusual.