[Knucklez]

my kitchen sink needs a vent. It will -eventually- be a large farmer sink type also with a dishwasher. Nothing else will be draining on this line when I'm done the reno.

above my kitchen is an attic and then the roof as it is just one story. If I bring the vent up on the inside of the wall as shown, then I could just bust through the 2x4 wooden top plate and entre the attic. Then come back towards the kitchen a bit and then straight up to the roof (don't want the vent right near the edge of the roof after all!).

but I am concerned that I will weaken the integrity of the wall/roof joint because the vent will cut entirely separate the 2x4 top plate on the wall (see circled area).

use of an air admittance valve is not going to work in my situation because of code requirements.

thoughts?

[ballengerb1]

Oops, had to first fix my error, I misread your issue. I would not worry, that plate does very little once the drywall is attached. You could go into the attic and attach a cross piece of 2x4 from one ceiling joist to the next joist, this should restore some stiffness. Where do you live that does not allow AAVs? Is the existing sink not vented at all right now and how did code let that get by?

[Knucklez]

Hi, thanks for the tip about cross-piece. I think I will do that.

And with the ceiling open for this vent work, I might as well spread more insulation around..


I'm in ontario canada. AAV actually are allowed, but.. they must be installed above the flood rim of your sink. Well, my sink doesn't have a flood rim, so if it overflows it just falls on the floor. So.. my "flood rim" is the top edge of the sink.

How to get an AAV above that? Well, it would have to be built into the wall, raised up above the sink and an access port installed.

But also code says aav must not be exposed to freezing temps.. well that wall is exterior, so probably it could get to freezing temp..

So aav is a no go for me in the kitchen.

My sink does not have a drain. There is also laundry sink using the same NO VENT drain in the basement. It gurgles like hell when the wash machine empties into it. If the sink in kitchen were full of water when the wash machine emptied you'd be inserious trouble. This is all wrong and needs to be fixed properly! Kitchen will have its own drain and its own vent to roof. Laundry system in basement will use its own drain (the one it connects to now) and an AAV. The drain pipe between kitchen/laundry will be removed. Kitchen will have its own drain going to main house sewage exit.

How did this pass code years ago? I suspect that it didn't. Probably no permits were pulled on the install. But it is galvanized drain and plumbing so its very old. Who knows, 90 year old home. Probably lots of stuff that is wrong..

One project at a time.. this house WILL get up to standards and will become safer for everyone. :cool:

Thanks for your time,
Knucklez

[speedball1]

my sink doesn't have a flood rim, so if it overflows it just falls on the floor. So.. my "flood rim" is the top edge of the sink.

Correct! All sinks have a flood riim. That's the edge of the tub. I wouldn't sweat cutting the top plate as it's being supported by the upright studs.
You do mhave a older home. I broke into galvanized drainage over 60 years ago. Good luck on your project. Tom

[Knucklez]

Perfect, now I am not afraid to take on this project. I'll be documenting the work and it will be posted in may time frame.

Starting with the vent :)