Hi I have a 25yr old summer moutain home that I have had for 5yrs. This place has always had a smell to the basement that leaches to the upstaires. The more I'm there the less the smell gets (but won't go away). This is a raised two story home, the basement is dry even if I did'nt run the dehumidifer. 2 drains in the floor with p traps. I also pluged the drains because they dry out. There is a sink with a j trap and a wahing machine that dumps into the sink. There is a pluming vent to the outside that is cealing high in the basement. Outside there is a floor drain p trap and a clean out that I recently install a breather on top. The rest of the house has j traps on the sinks and whatever are on the tubs. This smell seems to accumulate at the top of the stairs from the basement. If I''m upstairs and open the door to the basement, that's when I notice it the most. What am I missing? Thank you Jay Myers. [email protected]

Methane is odorless, that's why the gas companies put in a mercaptan agent so you can smell it. I will assume you are talking about sewer gas which is mostly methane but also has other chemicals in it and the bacteria breakdown is what you are smelling. "there is a plumbing vent...cealing high in the basement"? Don't quite understand what you are trying to say but if the vent pipe in open in the basment, that is your problem. Needs to vent outside and above the roof line.

It vents to the outside at that level and stops there. If it went above the roof line how would that correct my problem? I guess what I'm saying is how does it know its above the roof line or not?

If the vent just stops at the basment wall, you are probably backdrafting sewer gas through an open or leaking window or wall vent. When you use the drain, it dumps sewer gas out the vent and is pulled back into the house at the basement level. The main vent line is supposed to vent 1 foot above the roof. Venting as it does, it sounds like someone installed plumbing in the basement and decided to vent it the way it is. You can try to add piping along the exterior wall by connecting it to the existing vent, run it up to the roof line and see if that doesn't help. Exterior venting is used in Europe and in retrofitting older houses where it would be difficult to find and interior chase.

Thank you. I'm not trying to argue with you, I'm going for the education of it. But where it vents, that is a solid wall. I have no problem running a pipe 2 stories up the outside wall( just not today) Where the vent dumps outside and when inside flushing is accuring, I don't detect any gas oder around the vent. I think what ever is being dumped outside would be hard press to migrate back in.
Solid wall and Minamal to no gas oder at the vent. Also big 4" breather on the outside clean out. Newly installed next to a solid wall and a most of the time dry p trap outside 15 ft from closest door solid. I believe the system is breathing to the outside with no backdrafts at these points. Any other
Ideas. Thank you for your imput.