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Stubits · Jul 13, 2009, 09:53 AM

I am planning an addition to my home and am trying to figure out how to run some of the plumbing. The house is currently double wythe brick construction, so 2 of the 4 walls of the addition will be brick. Since space is at a premium, I am trying to figure out ways to avoid building out the brick walls too much, but the part that is killing me is the 2" vent stack.

I'm wondering, is it possible to create a channel in the brick for the pipe, like what is often done for wiring? If so, how deep and how wide can I go without risking the structural integrity? I am not thinking of fully embedding the pipe, perhaps just 1"? Does it matter if I am going vertical or horizontal? Does the distance matter?

21boat · Jul 13, 2009, 11:39 AM

Hi again stubits. Run into this a lot on our rehabs. A lot of this depends on the codes there. The old days in our all double brick homes one course of inside brick was channeled out for drainage and venting. The problem with that once in a blue moon the sewer line freezes and cracks in the wall since there is only one course of brick left.

Either or I would never channel in a vent or drainage for the basic reason of servicing down the road. Not to mention freezing the pipe with no insulation in drainage.

I normally buid a chase way for mechanicals. And soffits at times when in dire straits.

If its only 1" or so I wouldn't worry about that. But curious why only 1" for a 2" pipe which is wider then 2" O.D. How does this help?

Does it matter if I am going vertical or horizontal? Does the distance matter

Vertical is less evasive in structial change. Horizontal is a different story. The wall losses its compression ability's which is why it's there in the first place. The only reason you see a horizontal crack in a masonry wall is because of compression was lost on part of the wall. That's why you mostly see vertical cracks in masonry walls because of shear forces and why they get so big. That again is attributed more for a loss of compression then actual pulling away from the wall. Verticals usually show up first.
Again the codes there is the first hurdle for channeling into a structural brick wall.

Stubits · Jul 13, 2009, 11:50 AM

Hey man, thanks as always.

This is for a 1/2 bath and the dimensions are real tight, every inch counts. The architect is calling for the wall to be furred out with 2x2 for the drywall install, so I don't need the full 2+" for the pipe.

So, couple of questions. First, what do you suggest? Second, how much clearance do I need for a 2" pipe and if I furred the walls out with 2x3, would that work?

21boat · Jul 13, 2009, 07:12 PM

how much clearance do I need for a 2" pipe and if I furred the walls out with 2x3, would that work?

Again I don't know your codes there aside from that the pipe is 2 3/8 "OD. Don't forget if you put a coupling on that pipe it will be 2 7/8" wide. That's 0 clearance.

if I furred the walls out with 2x3, would that work?

That would work. Are these going to be tappconed in? If not I would just put up a 2x4 wall the other 1/2"

Can you explain why the 1" or so is so crucial. Is it because of the tub venting. A little more info here may help on exactly what you are running into. Also Are you running the water lines against that same outside brick wall? I would be concerned of freezing possibly. I try to Never run water lines on any outside walls.

hkstroud · Jul 13, 2009, 09:52 PM

Is this a vent or a vent stack? Check with Tom and Mark and local code, you may be able to get away with 1 1/2" if vent only.

21boat · Jul 13, 2009, 11:06 PM

but the part that is killing me is the 2" vent stack.

Stubits just to understand the difference of a vent or vent stack. There is a bit of word play here on definition.

Is this a vent or a vent stack?

Vent : A pipe that allows air into a drain system to balance the air pressure, preventing water in the traps from being siphoned off. Which this could be a AAV vent and not go anywhere other then above the trap

Vent Stack : Upper portion of the soil stack above the topmost fixture through which gases and odors escape.

Stubits · Jul 14, 2009, 05:26 AM

Thanks everyone. Sorry for any confusion. Let me answer a couple of questions here. This is for a half bathroom/powder room on the main floor of the house. There is 1 floor above it, but no additional plumbing above this location.

The bathroom will obviously have a toilet and a sink. My area allows wet venting, so this one vent will vent both the sink and the toilet. Mark has said I should use 2".

I am including a floor plan and a photo below to give a better idea of the situation. You'll see from the floor plan that the space is VERY VERY small and so we are trying to save every inch possible. You'll also see from the floor plan and the picture, that the brick wall I am referring to is currently an exterior wall, but after the addition will be an interior wall, so no real fears of freezing and the like.

What isn't immediately obvious, however is that the architect is calling for us to recess the sink into the current window space. According to her, this gives nice architectural detail AND it gives us an additional 4". We will be removing the brick below the window, but will keep the lintel and all the brick above.

I am ultimately trying to get it to the stick framed exterior wall so that I can get it up the next level and into the attic.

So, all that said, any suggestions? Further questions? Thoughts?

hkstroud · Jul 14, 2009, 06:03 AM

Check with Mark again, I believe 1 1/2" permited with some places requireing 2" when it goes through roof.

Stubits · Jul 14, 2009, 06:10 AM

I am under the impression that the sink needs to tie directly into it, no? Also, I would prefer, if at all possible, to avoid soffits and chases, unless totally necessary. But most importantly, I am not sure if, from a plumbing perspective, that would work.

The lower 2/3's of that wall (the toilet wall, so to speak) are brick as well.

massplumber2008 · Jul 14, 2009, 06:41 AM

Hi Stubits...

You definitely need the 2" vent as a minimum because you have a toilet here. The 2" sink vent is the wet vent for the toilet so only need to run this 2" vent up...;)

You said architect wanted you to install 2"x2" studs off the wall for sheetrock. You could install a 2"x4" wall as suggested by 21boat or if every little bit counts why not rip the 2"x4" studs down to 3" and install that... should accommodate the pipe and fittings in the wall without undermining the brick in any way (a 2"x3" is too small).

Let us know...

MARK

Stubits · Jul 14, 2009, 06:42 AM

Great idea, a true 3" would be sufficient?

massplumber2008 · Jul 14, 2009, 06:47 AM

A 2" PVC fitting is about 2.75" diameter... so 3" is plenty of room... ;)

Stubits · Jul 14, 2009, 06:49 AM

Awesome. I am checking with the architect to see if the 3.5" (with drywall) is going to kill us!

Now, this is complicated somewhat by her plan to recess the sink into the window area. That is to say, the sink will be recessed into the wall by about 4". Does that make sense and if so, any suggestions?

I tried to show it below...

massplumber2008 · Jul 14, 2009, 06:56 AM

Hmmm...

First thought that came to my mind was installing a small corner sink here... see images.

You could also purchase these very tiny sinks they make for just these cases... see last image.

Should save some room and perhaps reduce the need to embed the lavatory into the wall... maybe?

They also make corner toilets...

Just thinkin' aloud here... ;)

Stubits · Jul 14, 2009, 07:02 AM

We strongly considered a corner sink, but it just doesn't work, and with 3 brick walls, it didn't improve things much!

The sink we selected is similar to the third one you showed. The architect AND my wife both like the idea of recessing things for the architectural value.

Is it going to be impossible to plumb? Or is there a way to do it? In my diagram, I am thinking the vent is the circle on the left, and the line kind of show how the sink drain needs to travel. Can that work? Can a drain turn a corner like that?

I'm guessing there's no way to tie the vent in under the floor, is there?

massplumber2008 · Jul 14, 2009, 07:09 AM

The lavatory drain is not coming up from under the floor.. WHY?

No way to tie the vent in under the floor for this application (toilet and sink).

Stubits · Jul 14, 2009, 07:37 AM

Ok, I think I am just confusing things. My understanding is expressed in the diagram below. Is it close to being right?

massplumber2008 · Jul 14, 2009, 07:50 AM

Correct...

Then the way you drew the vent will work with two 90s back toward the wall... then can go vertical no problem (in the 3" wall).

Stubits · Jul 14, 2009, 07:58 AM

That will work? And be up to code? That's awesome! I figured it would present a clog risk of some sort.

And what's the maximum distance between the sink and the vent? Just want to make sure there's no problems.

massplumber2008 · Jul 14, 2009, 06:22 PM

Let's be sure we are on the same page here... review picture.

Vent clogging is not a concern if only using 3 - 90s before going vertical.

Maximum distance from drain to vent is not important here because the lavatory drain transitions directly into the vent. Just run vertical and out the roof and you are all set here.