Looked at a house yesterday. In need of updating the estate agent would say. Fairly untouched for a few years and a deceased estate. All in though it was a fairly good buy. Biggest obvious issue was uneven floors downstairs. The front room was raised in the middle by maybe 4 inches. A near perfect dome. Rear room had a bit of a dip. Lifted the carpet and the wood floor was in good condition. No spring, damp or wobble. The house seemed structurally ok, no lean or cracks. Didn't seem damp and it's been stood for 100 years. City terrace, no hills or streams but backs onto a local railway line. What might be causing this deformation? Alarm bells? What to check on a second look?