one other problem i am having the roof being flat, it will host a terrace in the future we not not have city sewers , so we have aseptical tanks installed ( is it how it is called in english?) anyhow, i did the plumbing myself, beeing quite a large job ...everything was planned so that i had 2 main straight runs that linked everything ( both bathroom are surimposed ) i ran the vents all together to a connection point in the ceiling/roof space of the second floor, and output through the ICF wall at the rear of the house when we take our showers and when weather gets colder, steam and hot air gets out of it problem is that it is only 10ft lower than the terrace roof, and the heat brings the odor on the roof which is simply unnaceptable also i've seen quite some ice buildup under the output point on the wall of the house in the last week since it got cold at night ... anyway to trap this and prevent the odor/hot air to move up and bring the odor with it ? thanks all cheers

You cannot trap a vent pipe, the air/smell is supposed to go out the pipe to protect the inside of the house. Your location of vent exit is the problem. It will smell, steam, etc. Is the vent pipe at least 3"? Vents are not supposed to be within 10 feet of any opening, window, air intake. Is it an option to continue the vent up to above the terrace level (maybe against some future railing post) to get it at least 7 feet above the terrace? I am not familiar with Canadian codes, but per IPC, if roof is used for anything other than weather protection, vent has to be 7 feet above roof.

thanks NFC for answer

we cannot trap it ?? too bad ..i thought that it would be a good solution

i've never experienced the smell during the summer/automn period

i don't really see how i could vent that 7ft higher than the terrace
other than using a very long pipe going up

the terrace has a 42" solid parapet and will get a 36" glass railing on top of the parapet to prevent children from climbing on the parapet
( it is a 40ft drop to the ground ..ouch )

but i am not sure the glass railing will suffice to deflect the odors

is there a restriction in length on that pipe ?

i could run it to the corner of the house where we have our exit to the roof ( 15'X15' room on the top )

but then there is a large balcony under this which gives to the kitchen ...

what does 7ft higher than terrace brings ??


thanks much

7ft higher than terrace puts it above human occupants, which is your current problem, as it is below. Unless Yao Ming stops by, 7ft should do it.

And think about it, a trap is designed to block air flow, so if you trapped the vent you may as well remove it and cap it (WHICH YOU CANNOT DO).

You may be able to extend it away from its current location, as long as you slope it back towards its current location, and insulate or heat it if it is outside. Talk to a local plumber or inspector. See if air admittance valves are approved in Canada, that could solve your problem also, as they only allow air in but not out.

Can you reroute the vent in the ceiling space and take it out another side of the building?

yes i can do that easily ..there is approx 20" of free space betwenn the bottom of the joists and the ceiling EPS

and it is mostly open for all of the ~1600sqft

why is it that i have never got the smell during summer?
colder inside the tanks than outside so the air doesn't go up ?

if it happends only during winter i could redirect it toward the other side of the house and have it output much higher so that i shouldn't get back to us


if at 7ft + the smell will go up with the air ??

cause it does smell quite alot on the terrace even though it would need to go past the parapet

cheers mate

I would be surprised if your code allows for side wall venting. Also if you extended it another 7 feet outside, it will get plugged with frozen condensate during cold weather.