Not to be confused with that sinking feeling, this was a smellier issue that confronted us the other week. Before I headed over to Casa Decrepit the Saturday past for some demo fun, K asked "does the bathroom smell funny to you?". Yeah, it did smell a little funky. Uh, oh. I mentioned it to Ayse that afternoon while we were working, and she said one of the most common causes is that "something's blocking the vent stack. You know, it crawled in the vent stack and died...but I mean that in the best possible way. :-)"
So I came home, cleaned off the roof (it gets slippery when there are lots of pine needles on it), and snaked the main vent stack. Over the next several days I tried various other things. I took apart the sink trap and snaked that drain and as far up as I could reach in its vent stack and lateral to the main. I checked that the shower trap had water in it, since a trap without enough water can allow sewer gases into the room, and we don't use that shower much any more. Snaking that drain is difficult because of the drain mechanism, but I tried covering it and the corresponding overflow. After each thing, there was no real change -- the bathroom still smelled funky.
So with much trepidation, I drained the toilet and removed it. I discovered two things: the flange was broken, and part of the gasket embedded in the wax ring was missing. Neither of those would necessarily cause the problem, but they were worth fixing in any event. I temporarily plugged the hole with a damp towel while I purchased a repair flange and a new wax ring. I had to chisel out part of a couple tiles in order to get the repair flange to fit, but I was encouraged I was finally on the right track.
With a lot of grunting (toilets are heavy), I lifted the toilet back into place, cleaned up the mess, and aired out the bathroom. All seemed well until a couple days later, when K asked, "does it still smell funny to you?". Arrgh! Indeed, there was a much fainter but still pungent smell noticeable. I then recalled having seen extra deep wax rings, and realized I probably needed one for this toilet because the repair flange and tile made for a slightly deeper space. So I purchased another wax ring, removed the toilet again, replaced the ring, and heaved the toilet back into place.
So far, so good. I haven't noticed any smell in a couple days, so the problem may finally be fixed. Of course, it could just mean my nose has gotten used to it, and the next guest will politely inquire if we've noticed that smell...