Bath tub & sink - shared vent


I first floor bathroom with a tub & a sink
Both seperately go up through the attic & finally through the roof. The tub run is about 11' tub to roof, the sink run is about 17' sink to roof.
The sink vent is run such that EVERY time I need to work in the attic, I have to struggle around the sink vent and I often hit my head on it.
the sink & tub vents are about 6' apart in the attic
Can re-route the sink vent such that it shares the tub vent roof penetration?
The point I would connect the two vents is about 2' below the roof. Becasue of the roof slope the "new" sink vent run would be about the same length as the current sink vent run.
So the actual shared would only be about 2' and my head would really appreciate the change.
Both vents are 1.5" galv steel pipe
cheers Bob
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I believe in most houses the tub and sink etc. are all vented together right from the bathroom. As long as they don't cause to much "vacuum" to suck the water out of the trap you are fine.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Assuming that there are no fixtures in the attic, yes.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Certainly it is OK to merge the vents in the attic and use a single roof penetration. Note that horizontal segments should be pitched like a drain so that condensation runs back towards the fixture.
As to the size of a merged vent, a 1.5" vent can handle 8 fixture units according to the UPC. A lavatory is 1 fixture unit and a bathtub is 2 fixture units, so a single 1.5" vent is adequate. I see a footnote in my reference that the UPC requires that vents be increased one pipe size if the horizontal length exceeds 1/2 the vertical length.
I assume that there is another vent elsewhere that is the full diameter of the house drain? This is required.
Yours, Wayne
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Wayne Whitney wrote:

Thanks for all the replies......
No fixtures in attic....thanks for the heads up about condensation drainage, "horizontal" run is about 6' but will follow 8/12 roof line
Wayne...."stacked" bath rooms have toilets with seperate vents that merge in the attic to a single 4" roof penetration...I assume that's what you meant by

cheers
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Wayne Whitney wrote:

than 3 feet between the drains. i am no expert. just check to make sure.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
jd karnes wrote:

You're probably thinking of the distance from the trap weir to the vent connection (trap arm length). That's different from the OP's situation. Jim
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

check your local code enforcement office. National codes are minimum requirements and many localities have more stringent requirements. Your local code may require separate vents thru the roof.
Don Young
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Site Timeline

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.