There may be others...
- Non-pressure-treated wood directly on slab.
- Non-fire-retardant-treated wood for pocket door framing.
Do they make a fire resistant wood pocket door?
Probably DWV piping given the size. Insulated for sound."This is the first floor that is a slab on grade" Are those ducts coming from below?
That would be my guess, too.Probably DWV piping given the size. Insulated for sound.