Our house is about 30 years old and when we are downstairs and someone is walking up stairs you can hear the floors making this squeaky noise. What is causing this noise? We are planning on replacing the carpet but wondering if we need the floors repaired? If we need them repaired, what kind of repairs? About how much would it cost?

Is your upstrairs hardwood or just a subfloor? You will know for sure by taking up a corner of the rug. Subfloors should be glued and screwed but can still come loose after 3 decades. Find the offending seam and put several 2.5" screws into the joist below. If its hardwood you need to predrill a pilot hole and countersink the screw head.

Yep - that's how its done

Wish it were that easy for me. Tried everything, still squeaks like hell.