Properly venting a toilet in Canada

Well, I bought two Toto Drake toilets based on recommendations here.

I seem to be having a problem with one of them, it just plain isn't flushing very well. This is the toilet in my addition. Upon climbing on the roof I don't see any venting, which I suspect is the cause.

The toilet in my main bathroom flushes excellently. The toilet goes right into the main 3" stack.

From what I can tell there were no permits on my addition - I don't think they would have allowed the bathroom in it with no venting and there's no heat runs in it at all.

That aside, I did find a 1.5" cheater vent on the sink. The 3" drain pipe runs about 40' into the main drain.

I'd like to fix this properly and have already contacted a roofer to deal with the torch-on roof. What I'm not sure about is what size of a vent and where I should put it. I could extend the drain pipe one foot and put a vent up the wall, so the vent would be upstream. I could do the same on the other side and attach the sink to it, so it'd be about a foot downstream.

Toilets don't need a full 3" vent, do they?

You can vent a toilet with 2" in your case. If the lav had been 2" downstream all the way for the vent that would work too. The sink or lav would be wet venting the toilet.
Have you pulled the bowl first and checked to make sure you haven't blocked the outlet of the bowl?
It sounds more like a blockage.
Sometimes the wax will drop off the bowl when setting and fall in the wrong place. Or someone used the toilet as a trash bin, and plugs it with broken tile or cardboard.
I would pull the toilet, bring it outside and try flushing it there. Then bring it back inside and try again.
Don't ever set a toilet in a bath tub unless you like to see chipped tubs and broken toilets.
It amazes me how many handymen will be too lazy to carry a toilet outside, they would rather risk chipping your new tub.

Thanks for the tips Terry!

The old toilet didn't flush well either. I suspect the 1.5" cheater vent just isn't enough air behind water for the toilet. That's the only venting I see for the toilet, unless it's vented in the crawlspace (I haven't had the pleasure of crawling under there just yet.) I actually think that cheater valve is not always operating which is another issue.

A good AAV is normally in the $20-$35 range.
I would replace with an Oatey or a Studor vent.

You don't need to seperately vent the toilet in your drawing there. Not only that but it's an illegal flat dry vent anyway.

You can wet vent the toilet through the sink, as long as the part of the sinks drainage that is both a vent and a drain (the actual wet vent) is 2" in size.

As it turned out, there was no blockage with the wax ring.

However, the bathroom in the addition was built so poorly (without insulation and heat) by the time I fixed them the room had become too narrow to put in a washroom, so I removed it, capping the drain near the end of the line into the ground and removing the tees for the supply lines and insulating appropriately.

Thanks for the advice here anyhow. :)

Unfortunately the cost of a roofer and electrician plus materials to rough in everything far exceeded any budget I had to fix the washroom correctly, so it was easier to remove it (there was no permit, so it wasn't supposed to be there anyway.)

IS flat dry venting illegal in NPC or is it just recmmended against by code? I know our city won't allow it at all though.

I'm curious, what is flat dry venting exactly and why is it bad? Is it ever appropriate to dry vent a toilet from upstream? ...and what if it is also wet vented downstream?

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Originally Posted by Esquire

IS flat dry venting illegal in NPC or is it just recmmended against by code? I know our city won't allow it at all though.

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They're illegal.

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Originally Posted by jdat747

I'm curious, what is flat dry venting exactly and why is it bad? Is it ever appropriate to dry vent a toilet from upstream? ...and what if it is also wet vented downstream?

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A flat dry vent is a portion of a vent pipe that connects to a soil-or-waste (SOW) pipe BELOW a nomially vertical angle. IE. The vent connects to the SOW pipe "flat". This is bad because eventually the vent is going to get plugged up because anything that happens to settle in there will not get flushed out by running water (which would make it a wet vent). And that flat dry vent pipe may be hard to auger, if not impossible without some serious work.

Flat vents (no such thing in the NPC) are really just horizontal vents and there certainly not illegal if installed above the horizontal center line of the soil pipe. A cleanout should be installed upstream however.