Plumbing help

Yoby

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I am doing a bathroom addition/remodel. Taking a large master closet and existing bathroom and making 2 bathrooms and a smaller closet. Called the local plumbers and they cant get to me for another month. So I'm taking on the project myself. Already have the framing and electrical pretty much wrapped up, but running into a problem with understanding the requirements of venting.

So there aren't any issues, I pulled a building, electrical and plumbing permit for the project. SD provides a little packet to aid, but everything I have researched and the packet doesn't really address my issues.

So my issues is a double sink vanity on an exterior wall. I know you cant go through the wall for freezing issues, but then again the code indicates horizontal venting isn't allowed. I attached my original idea (not the best drawing)

Any plumbers out there able to help a guy out with a couple questions?

15470956323323152948268932159405.jpg
 


eyexer

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where is the exterior wall? behind the vanity?

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I'm gonna go with the notion that the outside wall is behind the vanity. You can vent up outside walls that isn't a problem. You only need a 2" vertical vent for that situation. I'll draw up a picture and attach a picture of how to do it. I'm assuming you have 2x6" exterior wall framing? So just run a 2" vent line somewhere between the two sinks and down into the basement and tie into the sewer line. Just install a 2" cross into that vent line at 18" center up from the floor. Then run an 1-1/2" line out to each sink with a 90' coming out of the wall. Then install an 1-1/4" compression coming out of the wall for the sink drains to attach to. This isn't considered horizontal venting the horizontal runs are drain lines. Then just run that 2" out the stack. As far as insulation goes I would install 2" foam in the bays where the vent lines run. Then you can install fiberglass over the foam between the pvc pipes. Nothing will really freeze in there anyway because water doesn't sit in these lines it drains out too fast. I've done many this way over the years. That all being said, how you have yours drawn up would certainly work if that's easier for you to do as long as the far left drain isn't too far away from the vent stack. The code/rule regarding that is you can have a drain line 48 times the diameter of the pipe in distance from the stack. So a 2" line is 48x2=96 so 96" from main stack. Can't imagine yours would be that far away. All bathroom sink drain tail pieces are 1-1/4" so you just need to have an 1-1/4 compression at end of pipe to connect sink draining too. You can run 1-1/4, 1-1/2 or 2" piping for your vertical runs to your sinks in your drawing. I'd run 1-1/2 myself.


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D8C87645-F483-4ADF-BFAE-919DB0D8D35A.jpg
 
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remm

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I assume you are tying into the existing bathroom drain? If so, I also assume you are only adding one sink to drain to your existing setup? What I'm getting at is if you're modifying an existing bathroom and only adding one sink, why not tie into what you already have, I'd assume it's already vented properly and I doubt adding one sink would call for adding an entirely new stack, unless as noted above, you are moving the new stuff quite a ways away from existing plumbing.

I'm not a plumber, so just throwing that out there if it would be a possibility.
 


Yoby

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Thanks Eye, the only problem with that is my wife has purchased a vanity with drawer in the middle. I guess one solution is bringing each sink vent up to the attic and connecting them. I did not after you mentioned these lines could be in an exterior wall that what I read for exterior walls was "no water piping and traps ". I assumed this included drain pipes.

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and yes the back of the vanity is the exterior wall.
 

eyexer

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Thanks Eye, the only problem with that is my wife has purchased a vanity with drawer in the middle. I guess one solution is bringing each sink vent up to the attic and connecting them. I did not after you mentioned these lines could be in an exterior wall that what I read for exterior walls was "no water piping and traps ". I assumed this included drain pipes.

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and yes the back of the vanity is the exterior wall.
those sewer lines I have drawn are in the wall. go through the studs. only thing that will stick out is a piece of 1-1/2" pvc and the compression fitting for the sink trap/drain line. water piping is your water supply lines and traps hold water so can't do that either. But you can forgo the foam if you like. Just get a layer of insulation between the piping and the outside plywood and your fine. They don't hold water so nothing to freeze

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It’ll look like these under both sinks. DD3D55FD-ECCD-4449-8AE3-7669DBB55507.jpg
 

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