Olfactory Query

The half bath in my house smells funny. It sits in the middle of the house.. ie..it doesn't have any other walls that back up to anything so I know it's in that room. It's had this particular smell every now and again and almost smells like rotting wood, but worse. Some days it's really bad, and of course I notice it more than anyone.

Someone has looked under the house, nothing under there. I've checked all around the toilet and inside it, thinking maybe something is getting clogged up in there, nothing. The cabinet inside doesn't smell funny, it's like it's in the walls surrounding the bathroom, but only on the inside, not outside. Nothing looks rotten and when I tore the wallpaper off and painted, there weren't any wet spots to make me suspect a leak. And really with it all being interior walls, what could be leaking in the walls?

I took the vent cover off and washed it, so it isn't that.
It's been going on for months so I don't think anything could be dead in the vent or under the house. It would be gone by now.

It's driving me nuts, any ideas?

 

...hey pluto, you rock! now for your plumbing problem. the smell is coming from gas tweaking its way up into your home.
By gas, I mean the foul stinch in the drains that is supposed to be blocked by a simple "p" trap. You know, the loop of pipe under your sink?
Anyway, many times, that loop which is designed to hold water as a blockade to the backup of gases from the simple vanity drains or shower drains etc.
Do you have a bathroom that your family does not use anymore? Or do you have a shower that no one uses because maybe the kids are gone or whatever?
What happens is
the "p" trap water in non used drains eventually will dry up or lose its "block" of gas.
This one is easy to diagnose and damn hard to find.
Been there done that.
Good luck.
Your TBR admirer, Fishman

 

Fro needs to realize those mint toothpicks aren't dessert.