# Water lines in a basement exterior wall



## Stunt Carpenter (Dec 31, 2011)

Hi 

I'm not a plumber but I am trying to redesign a small basement bathroom. To try and open up the room to make it feel bigger I want to flip the tub and put the taps on the framed wall inside the concrete foundation wall. Is there a way I can do this without the lines freezing?


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## EthanB (Sep 28, 2011)

Put insulation between the plumbing and the foundation. If it's below grade you are actually less likely to see freezing than you would on an above grade exterior wall.

What form/quantity of insulation are you using on the foundation walls?


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## Stunt Carpenter (Dec 31, 2011)

I'm still in the planning phase. I'm not sure what would be in the wall now but I would try to upgrade it to a R20


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## Inner10 (Mar 12, 2009)

Stunt Carpenter said:


> Hi
> 
> I'm not a plumber but I am trying to redesign a small basement bathroom. To try and open up the room to make it feel bigger I want to flip the tub and put the taps on the framed wall inside the concrete foundation wall. Is there a way I can do this without the lines freezing?


Here we have to use 6mil poly, run the pipes close to the surface, insulate behind the pipes and put the VB behind the pipes.


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## Stunt Carpenter (Dec 31, 2011)

Can the same go for a tub/ shower mixing valve?


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## Inner10 (Mar 12, 2009)

I'd avoid it if possible.


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## cleveman (Dec 28, 2007)

If that wall has 2" of polystyrene on the exterior, I would not hesitate to put plumbing on it. The mixer will be mounted at about 3' off the floor, so you should have no problems.


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## EthanB (Sep 28, 2011)

The insulation is between the plumbing and the exterior so it is INSIDE the conditioned space. Freezing will not be a factor unless you have improperly insulated the space.

I recommend foam on basement walls, either spray foam or extruded polystyrene with taped seams, which makes the poly vapor barrier unnecessary and probably a bad idea.

You might want to spend some time reading up on basement systems at buildingscience.com if this is your first basement rodeo.


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## Stunt Carpenter (Dec 31, 2011)

cleveman said:


> If that wall has 2" of polystyrene on the exterior, I would not hesitate to put plumbing on it. The mixer will be mounted at about 3' off the floor, so you should have no problems.


Unfortunately this house was build in the 50-60's so no polystyrene.


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## Stunt Carpenter (Dec 31, 2011)

EthanB said:


> The insulation is between the plumbing and the exterior so it is INSIDE the conditioned space. Freezing will not be a factor unless you have improperly insulated the space.


I understand that but I am still getting a mixed message from people on here and plumber I have talked with


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## Chris Johnson (Apr 19, 2007)

Stunt Carpenter said:


> Unfortunately this house was build in the 50-60's so no polystyrene.


Doesn't matter when the house was built...you can use polystyrene between the studs.


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## EthanB (Sep 28, 2011)

Stunt Carpenter said:


> I understand that but I am still getting a mixed message from people on here and plumber I have talked with


He's a plumber, you need to talk to an insulation specialist.


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## Inner10 (Mar 12, 2009)

EthanB said:


> He's a plumber, you need to talk to an insulation specialist.


Specialist? Just cram some insulation back there...


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## Stunt Carpenter (Dec 31, 2011)

Chris Johnson said:


> Doesn't matter when the house was built...you can use polystyrene between the studs.


I know that but the original statement was polystyrene on the exterior


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## Chris Johnson (Apr 19, 2007)

Okay, now I am on the computer instead of mobile, you are in frigid Alberta, snow every month but July, so it's cold.

Rip the wall open, spray foam the cavity (for best results) second best use polystyrene (seal the edges and seams with spray foam cans) or thirdly use R-20/12 (depending on your framing member size) batts and put super 6 poly on top. Now place all plumbing in front of which ever method you choose. It's legal and it works

I'd personally suggest the DIY spray foam kit and at a minimum do this area only to ensure no issues, yes it's expensive but cheaper then tearing out a finished wall after the fact should you do one of the other methods and have a void which allows cold air to hit the pipes and freeze them, causing a burst.

Perhaps get creative with valve location so it is not on the outside wall, only have the shower head and spout there, ensure the water runs back to the valve from the shower head when not in use and positive flow from the valve to the spout, once not in use it all self drains without trapping or holding water.


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## Snobnd (Jul 1, 2008)

We do it all the time, Dryloc the walls 2 coats - add 2" insulation - then do the framing.


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## Oconomowoc (Oct 13, 2011)

Inner10 said:


> Specialist? Just cram some insulation back there...


You need a cram specialist


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## EthanB (Sep 28, 2011)

Oconomowoc said:


> You need a cram specialist


I think I can get you a recommendation for one of those. The last house I worked on obviously had one. You wouldn't believe how tight they could pack the R-13! They had half the stud bay left to work with.


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## Oconomowoc (Oct 13, 2011)

Lol


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## greg24k (May 19, 2007)

Stunt Carpenter said:


> Hi
> 
> I'm not a plumber but I am trying to redesign a small basement bathroom. To try and open up the room to make it feel bigger I want to flip the tub and put the taps on the framed wall inside the concrete foundation wall. Is there a way I can do this without the lines freezing?


You will be fine, to be sure, stay 42" bellow ground surface.


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