How to rid of odor from bathtub overflow?

July 25, 2016 4:45 PM

There was a rat infestation under the bathtub and wall/floor space. Yes..gross. It caused an odor issue coming out of the overflow. We took the tub out and cleaned out the area. Rat odor is gone...but now there is a different sort of odor. What to do next?

After consulting with a restoration company, these were the steps we did to take care of the rat odor:
1. hired a plumber and took the bathtub out
2. cleaned out the area
3. sprayed bac-a-zap - an enzyme spray to eliminate organic odor causing matters
4. the next day sprayed a full strength bleach.
5. after that's dry, several coats of Zinsser primer that supposedly blocks odor.
6. I tried to fill in any nooks and crannies with expanding foam to eliminate the possibility of rodents ever going back there again.
7. Tub goes back in

I cannot smell anything out of the overflow. But we can smell this sweet smelling stuff that permeates the bathroom. My theory is outgassing from the primer and since everything else is well sealed, there is one way out - to the bathroom via overflow or other gaps from the tub. I'm thinking of drilling a few small holes from the crawl space underneath to provide a path for those gasses to escape. Crazy idea? What else can I do short of tearing the whole bathroom down?

posted by 7life to Home & Garden (3 answers total)

The overflow is plumbed into the waste line from the tub. There is a trap in the line below where the overflow joins in to seal the sewer gases out. The only thing you can smell coming out of the overflow is the inside of a pipe about a foot long, and whatever is in the water in the trap - which should be water with a little soap.
Open a window, run the exhaust fan, give it a couple days.
posted by rudd135 at 5:08 PM on July 25, 2016 [1 favorite]

Zinsser odour blocking products are mostly shellac; the solvent used in the product is an alcohol of some sort so shouldn't smell sweet. Did the product smell sweet when you were applying it? If so the smell should lessen and dissipate with time; the minor amount of ventilation you could provide with some holes won't make much difference; especially now that the cavities are filled with foam (which won't really deter mice or rats unfortunately).

How long has it been? If it has been less than a couple months I wouldn't do anything besides leave a window open or fan on. Most building products that have noticeable odours will fully cure and stop smelling in 6-8 weeks.
posted by Mitheral at 5:10 PM on July 25, 2016

I had to say this, but I've learned that dead, decaying rodents smell sickly sweet to me. Perhaps some rats were either already dead in the negative space, or were closed up into the negative space and didn't escape before their demise. If so, I think 2-6 weeks and they should stop smelling.
posted by nobeagle at 7:40 AM on July 26, 2016