# False wall for exterior wall plumbing?



## Nealtw (Jun 22, 2017)

eblend said:


> Hi guys,
> 
> Quick question. I am out in Alberta, Canada, and was watching some YouTube videos of a local guy doing a false wall in his shower to run piping through along the exterior wall. Is this required?
> In his case, he had a 2x6 framed house. He insulated the 2x6 Cavity and then put on a vapor barrier, before framing a secondary wall right in front from 2x4s to run plumbing within. Is there no way to avoid this? I am building a new house and it will have 2x8 exterior walls with R24 spray foam insulation. The insulation will only take up like 3" of space, with free space to spare. I was planning on running plumbing pipes in the rest of the empty space (with some pipe insulation to boot), is that not allowed?


Our walls are 2x6, and in kitchens and bathroom they come up thru the floor and vent in the exterior wall but the utility room is just like you described. You will have to ask about your 2x8 walls.


----------



## SPS-1 (Oct 21, 2008)

Yes, I think the bump out is pretty much the best way.

I had the same situation. Only 2x6 walls, but I would not want pipes inside the exterior wall.
Actually, it worked out very well. The 4" step was perfect for putting a towel bar without the shower door hitting it. (Hinge side for door always on structure)


----------



## wigginsr181 (Nov 18, 2021)

Not necessary when the house is heated and the plumbing is installed on the warm side of the insulation . If the heat fails , unless you provide heat in some way , you're going to vacate the house and the system should have provisions for draining .


----------



## Nealtw (Jun 22, 2017)

wigginsr181 said:


> Not necessary when the house is heated and the plumbing is installed on the warm side of the insulation . If the heat fails , unless you provide heat in some way , you're going to vacate the house and the system should have provisions for draining .


He is building new so it is about code not really about what works or not.


----------



## eblend (11 mo ago)

Thanks for the feedback. In my current house I do have one location where there is a pipe in the wall, and when it gets to -20C the cold water line will freeze unless constantly dripping. I have insulated the pipe as much as I am able to get to, but it appears to be freezing at the sill plate. I will only have one location in the new house where this would be a concern, but the pipes will be coming from above in the heated space, and not through a slab or anything like that. I was thinking of this yesterday and perhaps the bump out is more for the fact that there is the whole mixing valve in there as well, and not just pipes.


----------



## Nealtw (Jun 22, 2017)

eblend said:


> Thanks for the feedback. In my current house I do have one location where there is a pipe in the wall, and when it gets to -20C the cold water line will freeze unless constantly dripping. I have insulated the pipe as much as I am able to get to, but it appears to be freezing at the sill plate. I will only have one location in the new house where this would be a concern, but the pipes will be coming from above in the heated space, and not through a slab or anything like that. I was thinking of this yesterday and perhaps the bump out is more for the fact that there is the whole mixing valve in there as well, and not just pipes.


You could always bump the outside wall out so you would not notice it from inside.


----------



## eblend (11 mo ago)

Nealtw said:


> You could always bump the outside wall out so you would not notice it from inside.


Yah it's possible, just not very desirable as it's a long wall. I will try to convince the wife to have the shower head on the interior wall, she wants it on the outside wall. The shower/wet room in the top right corner here:


----------



## wigginsr181 (Nov 18, 2021)

Nealtw said:


> He is building new so it is about code not really about what works or not.


So the code folks are lacking in important knowledge . I'm thinking they don't know that without a heat source the water would eventually freeze if between 6 walls . Sometimes i can't help but feel sorry for code people .


----------



## Nealtw (Jun 22, 2017)

wigginsr181 said:


> So the code folks are lacking in important knowledge . I'm thinking they don't know that without a heat source the water would eventually freeze if between 6 walls . Sometimes i can't help but feel sorry for code people .


We are in zone 4-5 and we see lots of problems with plumbing in outside wall with out loosing heat in the house. 
The OP is is in a much colder zone than where I am.


----------



## SPS-1 (Oct 21, 2008)

eblend said:


> I have insulated the pipe as much as I am able to get to...


You might not have it insulated correctly. Don't wrap it in insulation. You want insulation behind the pipe, so it doesn't lose heat to the outside, but don't put insulation in front of it, so heat from the conditioned space can reach the pipe.


----------



## eblend (11 mo ago)

SPS-1 said:


> You might not have it insulated correctly. Don't wrap it in insulation. You want insulation behind the pipe, so it doesn't lose heat to the outside, but don't put insulation in front of it, so heat from the conditioned space can reach the pipe.


Yah it's possible. It's an inaccessible area, could just get my hand in there barely. I slid pipe insulation over the pipe that I could feel, that's about it. I was going to take the pipe out completely and come in through the floor as the new vanity would allow for it, but never got around to it, and now that I am moving out soonish, I don't want to bother. I usually just let it drip a bit while cold. The few times it froze it has been okay as it's PEX, so I haven't been too concerned about it in this house, but want to make sure same thing never happens in the new place. That's a good point though, never really thought about the fact that it being insulated also insulates it from interior heat.


----------

