We purchased our home around 1 year ago and in the last month the floor drain in our bathroom downstairs has a smell. I have tryed everything draino, caustic soda, bi-card etc but nothing seems to work. The bathroom upstairs is fine.
The renovation would be approx 3 years old and they used an old dresser for the vanity and there is no S or P bend in the pipe it bends to the left 2 times before entering the concrete floor. – could this be the problem?
Sounds like your Vanity has a S trap on it. Go to http://www.google.com and ask what S trap looks like. on the floor drain has it a trap, try pouring Bio Clean are Pine oil are San Teen I dont know where to get it but you can check on web site i am sure you can find it there.
Regardless of what kind of trap (if any) your lavatory has, the floor drain (like any other drain) must also have a trap. Some don’t. You should check that first. Shine a flashlight into it. You should see water, or if you can’t see into it, stick in a length of wire as a “dipstick.” When you pull out the wire it should be wet. The trap may have dried up due to evaporation (a common problem in floordrains). Pour a half gallon of water into it, and that may stop the odor. Also, run water down your fixture drains and listen at the floor drain. If you hear a load gurgling sound, the trap may be siphoning out as water drains into the building drain. That would indicate inadequate venting to the other fixtures on the line.