Hi. First of all, this is a condo, not a house, top floor and no attic. I had a strange issue. Smell in 2 bathrooms, one with bathtub and the other with shower. Long story short. Handyman cleaned shower drain, used a snake as well, dumped there some chemical and sealed the toilet, also opened wall under the sink (nothing was there), and smell in shower bathroom is gone, just smells dump time to time, but ventilation in both bathrooms sucks, only by weak exhaust fan (no windows).
The other bathroom with bathtub is major headache. That smell started strong in that one. Same handyman opened the wall under the sink and found rusted drain pipe, changed, placed new pipe with the trap to the outgoing drain pipe, sealed the wall, painted. Toilet sealed as well. Result, same smell persists, just less obnoxious. So, I decided to make a small test and dumped vinegar into all 3 drains in this bathroom - repaired sink, toilet and bathtub. After vinegar smell was gone, it was no any smell for about 4 hours.
I am planning to open the wall behind the bathtub drain for inspection and probably remove the toilet and check wax seal. Anything else I missed.
It smells not organic (methane or ammonia or mold), not dump, some kind of very sharp odor I don't think it is sewer gases out venting somewhere. By the way, I noticed that inner piping is some kind of plastic (maybe PVC), I don't know yet what kind is bathtub drain. Also, previous owner has done extensive remodeling i both bathrooms with tile floors and tile around the bathtub, I doubt her plumber would miss anything leaking. According to HOA, bathtub and faucets were changed.
Any other ideas? I seen and read this post already
Any suggestions are appreciated Thanks in advance