# Locating plumbing in an outside wall



## Mike Finley

I have seen some references to locating plumbing in outside walls as either a resounding yes, or an equally adamant, no. As far as I have seen there is no code in regard to an outside wall is there? What is your take on this? It seems there are two schools of thought, one being with enough insulation it is okay and the other school of thought being never.

It has just occurred to me that I have never had to deal with it before, but we have a project coming up where the shower plumbing will need to be on an outside wall. One thing I have considered is leaving the existing finish of the interior wall as is and firing a brand new wall (just the width of the shower - which would be 36" on that wall)against it and running the plumbing through it.


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## Teetorbilt

I'd go with plan 'B'. Outside plumbing where freezing can occur is asking for trouble. Bumping out a wall a few inches is child's play.


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## mdshunk

I dunno Mike. Here in the northeast, plumbing in the outside walls is avoided, but still done from time to time for various reasons. Generally, they drill the water line holes right into the front edge of the bottom plate (almost a notch) and put nail plates over them. The insulation is put completely behind the pipes, essentially putting the pipes "in the room", even though they're behind the drywall. Seems like your idea is basically the same thing, except that with your furred out wall, you'd have more R's stuffed behind the pipework, which you may or may not need.


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## Double-A

With today's variety of shower valves, mixers, diverters, body sprays, euro spas and the like, its rarely necessary to actually put the mixing valve on an outside wall. 

If you do, there are several things to consider. Access for future replacement. Nothing lasts forever, the valve body might have to be replaced someday. Putting this in a wall where you can just cut into and make a repair (as in dry wall) makes more sense than cutting an outside wall.

Freezing weather is another factor. The pipes and valve body need to be well insulated to withstand freezing weather or you might be tearing out that surround to replace the valve body.

Furring the wall or moving the mixer to the back or a side wall off center might be the best compromise.


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## ahamedibrahim

Hello

Thanks Administrator for your advice.

I am a Newcomer.

I am an Engineer in the Plumbing Field working in Dubai from 1979.


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## Peladu

Fact: Hot water freezes faster than cold water.


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## Tom R

Peladu said:


> Fact: Hot water freezes faster than cold water.



Alright, I'll bite, - - Why is that??


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## Double-A

Peladu said:


> Fact: Hot water freezes faster than cold water.


Yes and no. Demonstrating the Mpemba effect can take place under a variety of circumstances, but not in all circumstances. So... 

Theory: Hot water can freeze faster than colder water under certain conditions.arty: 

Take a look at this link for a more detailed explanation.


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## Double-A

Tom R said:


> Alright, I'll bite, - - Why is that??


 
No one knows for sure, Tom'r, but they have several theories.


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## Peladu

Holy crap guys, you are all caught up with the riddles going around that you seem to think everythings a riddle...:laughing: 

Hot water freezes faster, why? I dunno, and dun care..it just does.
I would never put plumbing on an exterior wall, no supply lines, but maybe waste lines..


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## Peladu

But I want to nominate Battery as the official CT info-looker-upper-dude.


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## Tom R

Peladu said:


> Holy crap guys, you are all caught up with the riddles going around that you seem to think everythings a riddle...:laughing:



You mean, - - it's not a riddle??


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## Mike Finley

Okay, I should have been clearer. What I'm asking is how do you feel about putting plumbing in an outside wall?

Who cares?
Never gonna do it!
Do it only if I have to.


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## Peladu

If the only, and I mean only, option left was to place supply in an exterior wall, then......maybe.
I have not run into the situation to where I had to do this.
Sure I have had customers want the mixing valve and head on the other side of the shower, but I tell them it can't/shouldn't be done.
Mike..honestly, I would avoid it at (almost) all costs.


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## Double-A

Its not the best place for it IMHO, Mike. If they insist, I'd furr the wall out at the least, but if they are leaving it up to you, I'd make the best compromise I could before putting it on an outside wall.


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## smellslike$tome

*Plan Bbbbbbbbbbeeeeeeeeeeeeeee!!!!!!!!!!!!!!!!!!!!!!!*

Never place water distribution piping, fittings, or valves in exterior walls unless there is just no other way which should never be the case with respect to a shower, unless it's located in a corner with a glass block or glass outer. However, sometimes it may be unavoidable with respect to kitchen sinks or lavatories or even washing machine connections. If it is necessary then it should be pex water piping with brass fittings and everything should be sheathed with armaflex. I would never want to put copper in an exterior wall anymore and I definately would not put cpvc in an exterior wall, insulated or not (I never use cpvc except in repair situation in which cpvc is already present and even then I don't like it).


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