I live in an industrial loft. My downstairs neighbor is a factory. When they're running, fumes come up through my bathroom into my apartment. It's serious problem.
The guy who lived here before me put in the pipes himself (he left behind the tools, even) and I'm guessing he did a slapdash job of sealing around them. I'd like to find the penetration that the fumes are coming through, make an airtight seal around that pipe, and live in peace and harmony with my downstairs neighbor once more.
Problem step 1: How do I figure out which penetration is leaking fumes? (Some of the penetrations, like the 3 water lines to the faucet, are closed off behind a boxy sink, too.)
Problem step 2: How do I seal it?
Best Answer
Solution step 1: Just seal all of the penetrations you can find. If that doesn't help, you'll probably have to start tearing off drywall to get at hidden pipes if you're sure the smell is seeping through gaps between plumbing and the floor.
Solution step 2: Use Spray-applied polyurethane foam. Dow Great Stuff works well. Just be sure to wear gloves!