Smelly floor drain

whammytap

OK, here is a problem that has been bugging me for some time. The floor drain in our laundry room, which has a concrete slab floor, is normally odor-free. I make sure that water frequently goes into it (and I think the washing machine drains into the same pipe just past the floor drain, too) so it is not a dry pipe. But when we turn on the attic fan, a bad (sewer gas?) smell starts issuing from the laundry room. So it takes a negative-pressure system to pull this smell out from wherever it is coming from, I suspect the drain.

Anybody have a fix for the problem? We really can't afford to have the whole shebang dug up and re-laid, is there a DIY repair or a quick fix I could do? I have had limited, short-term success with putting vinegar water down the drain.

Thanks!

plumberinlaw

First seal the drain with duct tape and plastic. Second turn on whole house fan to check if it is really coming from the floor drain. There could be another source so you need to confirm or exclude the drain.

bob22

While we're at it, I'd be a bit concerned about the exhaust from gas appliances (water heater for example) being drawn through the house when the fan is on. Carbon monoxide detectors should be installed if you've gas appliances (range, dryer, water heater, furnace).

whammytap

We have gas appliances, but when we turn the whole house fan on, we open a window in each room. The utility room is also the laundry room and pantry, so if they're leaking CO it would be building up worse when the fan isn't on. Our house is of the old-fashioned, "drafty" or as we prefer, "naturally ventilated" construction technique. I understand that radon and CO is mostly a concern for newer construction in which vapor barriers have been employed.

Plumberinlaw, I did as you instructed and have confirmed that the smell is coming from the drain. What should I do?

Otherbill

if you can, try installing an outside vent pipe on the discharge pipe several feet from the house. Install a "T" pipe, it worked for me.

whammytap

Thanks! I will look into that.

Otherbill

you might try somethings like this. Or try doing a search likw this--vent traps for floor drains.

could be a blocked vent pipe. It may need snaked out.

http://www.thesureseal.com/Default.a...FUTf4AodoX3-EA

bluebird5

sounds like the drain is not trapped. can you access it somewhere and install a running trap?

whammytap

The more I think about it, the more I think it probably isn't trapped. It's hard to get a good look at because the washing machine sits directly on top of it. This house is from the first wave of post-WWII houses, so it was thrown up quickly. I guess I'll add this to the list of things that weren't done right the first time.

This floor drain is built into a slab floor, too, so no access from underneath. Let me guess--at least part of that slab is going to have to come up for the drain to be re-worked, which is beyond my level of expertise/price point right now. Guess it'll have to wait for that room to be remodeled--the walls (which aren't even drywall, they're chipboard-type stuff) are half rotten anyway.

Thanks everybody for the help and good advice!

bluebird5

You a floor drain really insn't necessary. The only reason it weould be useful is if your basement flooded. I would get some good strong sticky tape and cover it. Run one row front to back and another layer left to right and that should take care of the odor

whammytap

We don't have a basement. That part of the house is slab foundation. We do need the drain; that's where the central air unit drains to. Kansas summers are very humid, so the drain takes 10+ gallons a day in July and August.