# Venting through roof



## Pickelk (Oct 21, 2012)

What size of pipe do you need to vent through the roof in Alberta if you are venting 1.5-3"for main stack and sink vents


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## OldSchool (Jan 30, 2010)

I pretty sure it's 10" pipe depending on the cfm of the fixture .. Could be greater


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## 504Plumber (Jan 26, 2011)

God no, 10" is way too big. We usually reduce down to 1/2" PVC that way there is less chance for a roof leak.


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## OldSchool (Jan 30, 2010)

504Plumber said:


> God no, 10" is way too big. We usually reduce down to 1/2" PVC that way there is less chance for a roof leak.


That would work on a one bathroom home seeing the cfm is only 2.5 per bathroom group


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## revenge (Jun 30, 2011)

bush it down to 3/8 tubing no need for roof flanges just use silicone


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## OldSchool (Jan 30, 2010)

revenge said:


> bush it down to 3/8 tubing no need for roof flanges just use silicone


Don't you think that would cause back pressure .. Could back up the toilet


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## 130 PLUMBER (Oct 22, 2009)

10" sounds good to me:thumbsup:


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## revenge (Jun 30, 2011)

na it still will work no probs gauranteed


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## 504Plumber (Jan 26, 2011)

revenge said:


> bush it down to 3/8 tubing no need for roof flanges just use silicone


Problem is you are mixing materials.

Section 420.3: thou shalt not dissimilar the metals.


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## revenge (Jun 30, 2011)

you can use poly tubing, it cheaper than copper and only one connection is need just roll out the rest use nails bent in u's for support and your done


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## okcplum (Jul 16, 2011)

I would go with 6" to be safe but only if its a 1 bath home.
10" is a little large but I guess it would work.


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## OldSchool (Jan 30, 2010)

mark kiernan said:


> I would go with 6" to be safe but only if its a 1 bath home.
> 10" is a little large but I guess it would work.


Bigger is better ... When in doubt make it larger


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## Tommy plumber (Feb 19, 2010)

OldSchool said:


> I pretty sure it's 10" pipe *depending on the cfm of the fixture* .. Could be greater


 






cubic feet per minute for fixture...........:laughing:........don't forget how many air changes per hour


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## The real E.P. (Aug 9, 2011)

3 inch minimum thru roof because of hoare frost


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## U666A (Dec 11, 2010)

OldSchool said:


> Bigger is better ... When in doubt make it larger


Close... Upsize 1 trade size. 12" will suffice.


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## Mississippiplum (Sep 30, 2011)

You gotta use 10 inch black iron with victaulic fittings

sent from the jobsite porta-potty


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## plbgbiz (Aug 27, 2010)

I may need to defer to OS on this but I think Canada doesn't even allow roofs on structures where vents are needed.


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## U666A (Dec 11, 2010)

plbgbiz said:


> I may need to defer to OS on this but I think Canada doesn't even allow roofs on structures where vents are needed.


We're in the same province, same code. The wood butchers just leave out one block near the top of the igloos... Dwelling vented! :thumbup:


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## Redwood (Sep 8, 2008)

Just cut a moon shaped hole above the door and you'll be fine... :thumbup:


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## user4 (Jun 12, 2008)

If you terminate it in the attic you minimize the chance of roof leaks.

Just tell the homeowner to buy extra air freshener.


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## plbgbiz (Aug 27, 2010)

Maybe the OP can try again tomorrow. This thread is pretty much toast.


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