Saw a first today… not sure if it will fly, and definitely looked odd. New house with rough plumbing going in. They brought the master bath (2″) and kitchen (1-1/2″) vents together in the attic, then converted to 3″ before penetrating the roof. So, right below the roof line is a 3″ tee with a 3″ riser out the top, a 2″ reducer coming in the side, and a 1-1/2″ reducer coming in the bottom. Looks all bassackwards, but will it pass? I’ll probably be there punching out the framing in a few days and will see what the inspector says.
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Works here. 3" through the roof is mandatory, would prefer the 3" long as possible in the attic to help prevent frost buildup.
David,
It is legal, it is okay, and I think it looks better to tree the vents than to have multiple penetrations. I remember an inspector in snowy Colorado asking me to go to 4" through the roof because of the frost closure issue.
Bill
I did it, but I brought (2) bathroom, laundry room and kictern into one stack. brought the kitcern from the other end of the house 30 feet. as long as there a slope and each area has a cleanout, what could be wrong with it.
Very neat job on everything in that attic !Well done, Johnnie !
Are we there yet ?
Had to do a similar thing in my house, 1 1/2" straight into a 4" through the roof, required by code.
Dan
"Life is what happens when you are making other plans." - John Lennon
Got it... it's just that it looks backwards to me. Pipe usually gets bigger as it gets lower. I'm used to seeing a 3" or 4" vent from a water closet, and the other vents join that line below the roof.
It's fairly normal (code around here) to require a vent to increase one size as it penetrates the roof. Reduces the chance of frost clogging the vent.
Yeah, that'll look "upside down," but vents "want" to do just like drains, and get larger.
If you are used to seeing a common vent that everything else T's into, it can look right odd. Bring a 3" vent off the 3" drain from the w/c and "leg" the other vents into that, and it look "normal."
in washington your instincts that some thing is wrong would be correct . what you see is an attemt to supply the ventting so the diamiter of the exiting vents equal the diamiter of the waste pipe leaving the home it is called cross sectional venting it would be hard to explaine without seeing . but you cannt do what you discribed
I understand that these guys are trying to make sure the cross-section of the vent leaving the building is equal to the cross section of the sewer. There really aren't frost issues here... if we have freezing weather for 24 hours it's highly unusual.
The toilet is very close to where the transition I described it... not more than 5' away horizontally. They coulda just run 3" all the way up.