We recently have found that sewer gas is coming from our basement floor drain. The floor drain has water in it and is draining properly. I did notice that there is a vent just above water level in the drain. Is this normal?
All of the drains in the house seem to drain normally but now this smell is noticeable in the basement.
As I thought about this problem I considered that the gases should be venting to the outside through the roof vents. I went out side, where it is still between -17 and-22 deg Celsius, and took a look at the roof vents. I noticed that there was ice sticking out the top of one of the vents (there are 2). Could this vent be plugged with ice? Could this cause the sewer gas to back up into the basement?
Is there anything that can be done to reduce the gases until the ice melts?

Hi Pollypods:

At those temps... sure as heck likely that the vent is iced up... ;)

Tell me, are the vents accessible in the attic right before they go through the roof? If so, you could use a paint stripper heat gun (best), an electric blanket (next best), or a hair dryer (works fine, but need to take breaks in between use so you don't burn the element out) and heat the pipe just before the pipe leaves through the roof... ;)

It may take some time, but if you heat the pipe slowly, over time, it will thaw out and the ice should melt away. You would confirm all by going outside to see that no ice is sticking out the vent.

If the vents aren't accessible you could also try to run lots of hot water and hope some of the steam makes it up there to start to melt this a little bit. However, I don't see this helping if the vent is totally clogged with ice.


Now, in terms of this VENT at the floor drain.. Are you sure it is not just a plug so that something can connect directly into the drain.. Let me know more here...

Back to you..

MARK

Just to be sure, can you post a pic of your floor drain. Im thinking that the opening right above water lever is a cleanout, which should be plugged at all times(should only be removed when snaking the drain, then plug should have been put back in). Most likely the reason you are smelling the sewer gas now, is because your vents are frozen, so the gas is coming out the cleanout. Either way, the opening above water level in the floordrain needs to be capped or plugged. For now, just stick a rag in there and see if the smell goes away. If it does, get the correct size plug and plug it off.

Hi Mark,
Thank you for the quick response. The access to the attic is very limited but I will try to see what I can do to un freeze that vent.

The floor drain has what looks like a standard 2 inch opening coming into the side of the large diameter floor drain. The opening is about half way in / out of the water. I can't remember if in the past this smaller opening was covered with water or not. I tried to raise the water level in the drain by pouring buckets of water into the drain, but the water level always goes down to the same level.

Is there a way to post pictures on this site?

Does your floor drain look similar to this?

22 degrees Celsius is about 72 degrees fahrenheit, are you sure of what you are saying? I am going to guess you confused the terms centigrade, Celsius and fehrenheit. Celcius and Fahrenheit Converter (http://www.stabb.com/tools/convert.html) Use this to convert. Now if you actually mean 22 fahrenheit I could picture frost building up on your vent stack but it is more likely to freeze when it gets below zero, fehrenheit

-20 c = - 4 f . Cold for sure.

Darn, the way the letter spacing happened I missed the negative which was on the previous line. -22c+ -7.6f , formula C x 9/5 plus 32 = F