On Feb 7, 7:26 am, (m Ransley) wrote:
Of course the builder would say there is no structural problem , get out
a few pros to find and verify the issue in writing, so you know what to
demand from your builder now and in court if needed. Document and
photograph everything. The building inspector, an engineer, or architect
and contractor is needed. The inspector is free.


It's possbile it's structural, but not that likely. It's very
common for floors that were done fast and cheap to have this problem,
which makes noise abnd is very annoying, but doesn't mean the
structure isn't sound or is in danger of failing. To be done
properly, the plywood should have been glued with construction
adhesive, as well as screwed or nailed (screws are better). If done
improperly, you have this problem, but I doubt it meets the definition
of structural in new home warranties.

When the floor was screwed down, did they put screws no less than 6"
apart along all the joists? In this difficult case, I'd put them
every 4" If that doesn't solve it, then depending on what sound
remains, I might consider opening the ceiling below, depending on
area, etc, so that you can inspect the suspect joists hangers,
nailing, etc. Taking out the ceiling might be easier than removing
the flooring.