Pipes on Outside Wall

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Old 01-20-21, 08:49 PM
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Pipes on Outside Wall

I looked at a bathroom remodel in process today. I thought I was seeing things...water pipes run on an outside wall. When I asked the guy in charge about it he said yeah "we're going to put foam board back there."

Am I missing something? I've seen copper pipes freeze this way. Is pex that much more impervious?

If it means anything, there's vinyl siding on the outside of the cinder block. Also the location is SE Michigan.


 

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01-20-21, 09:12 PM
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Yes.... PEX is more forgiving but no one with common sense puts plumbing in an outside wall in a cold zone.
 
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Old 01-20-21, 09:12 PM
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Yes.... PEX is more forgiving but no one with common sense puts plumbing in an outside wall in a cold zone.
 
CasualJoe, Norm201 voted this post useful.
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Old 01-20-21, 09:22 PM
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Is that a 2x4 wall or 2x6 wall? I would think that it should have been 2x6 in order to be safely on the warm side of the insulation.
 
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Old 01-20-21, 11:50 PM
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Just confirming, is that a basement wall?
 
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Old 01-21-21, 06:15 AM
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As Marq indicated, is that a basement wall? And if below grade then pipe on outside wall is OK.
I know a guy who lives in a townhouse. Bathroom piping is on an outside wall. He left for a vacation and came back to a flooded house. He must now shut off water supply every time he leaves the house.
 
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Old 01-21-21, 06:34 AM
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Thanks for the replies. It's not a basement wall, nor are they 2 x 6 studs...
 
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Old 01-21-21, 06:40 AM
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Before they close up that wall I would reroute the plumbing.
 
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Old 01-21-21, 06:48 AM
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Or insist that they notch the studs to put the pex as close to the drywall as possible, then cover them with no nail plates. And still use foam behind them. As much foam as possible... air seal the edges of each layer of foam.
 
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Old 01-21-21, 06:53 AM
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Unfortunately, It's not quite my job to dictate on this X...I'm just an out side observer.
 
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Old 01-21-21, 07:03 AM
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Pex is easy and flexible. Should be no problem with rerouting. I'm not keen on the notching suggestion. Would that even be to code? Seems like as much work if not more. Then you have "non-standard" wall. I've seen a re-piped house (actually my daughter's former house) that used a multivalve manifold coming off the main as it entered the house. Al the pex lines were branched off of that. They were then able to bring the pex piping to inside walls with either another manifold or valve to "zone" each area. The only piping that were on an outside wall was the kitchen sink. But they were inside the dwelling and not inside the wall.
 
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Old 01-21-21, 08:45 AM
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OK....I've decided I'm going to tactfully try to put another stronger bug in the contractor's ear about this being a problem...even though we don't know each other. That is all I can do. We'll see how he responds.
 
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Old 01-21-21, 09:59 AM
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You can notch 25% in a load bearing wall. The notch would be roughly 3/4 deep which is 20%. And this is likely not a load bearing wall. Non load bearing walls can be notched 40%.
 
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Old 01-21-21, 10:15 AM
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During a bathroom reno years ago I put PEX shower supply pipes in an outside wall. The wife wanted a glass shower and only outside walls were available for plumbing. I doubled the wall where the vertical pipes were run and I used 4" of foam board (R-20?) in the empty outside stud cavity plus I tucked unfaced batt around the pex pipes in the inner wall cavity.

The pipes froze - twice. Granted, both times it was below zero outside. Fortunately the pipes didn't burst. I'm glad I used PEX because copper would probably have failed. After that we were sure to drip the shower on very cold nights.

That shower has since been rebuilt with the plumbing on an inside wall.
 
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Old 01-21-21, 10:34 AM
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OK....I've decided I'm going to tactfully try to put another stronger bug in the contractor's ear
Who's paying for this? If it's you then you demand he do it correctly. Check with your local codes and insurance company. I'm betting they will not approve of water pipes on outside walls.
Look at what CW's experience was and how much insulation he took to it. And still had problems. This is a clear case of learning from someone else's experience.
Show these post to the contractor, maybe that will make him think.
 
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Old 01-21-21, 11:50 AM
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Did you say in an outside wall or on (the outside of) an outside wall?


For pipes in an outside wall I suggest no insulation between the pipe and the inside wall surface. Do not use pour in insulation. For batts, run them behind the pipe or slice out a V shaped notch following the route of the pipe as wide at the wall surface as it is deep.


A pipe must never be run on the outside wall surface in a cold climate without heating tape wrapped around it. Even so it will be a constant worry in case of power failure.
 
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Old 01-21-21, 11:58 AM
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And you shouldn't conceal pipe wrap inside a wall. Ask any fireman.
 
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Old 01-21-21, 07:31 PM
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I was thinking I was pretty clear about the post details with the picture included, and my subsequent info, but perhaps not, with seeing some of the responses.

As I have stated, I am an outside observer (It is not my house.) that has raised an eyebrow to a dicey situation. I have expressed my concerns to the contractor clearly. It is not up to me to insist anyone do anything.
 
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Old 01-21-21, 08:20 PM
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Not everyone reads 100% before replying.

PLUS, I think, most of us assume right off the bat that when someone asks a question and posts pictures from inside someone's home, that he IS the homeowner, otherwise he wouldn't be taking those pictures, posting them, and asking questions.

I know your post didn't read that way, but the forum is largely for answering diy questions that homeowners have. That is typically the mind set with which anyone who is quickly skimming the forums would have, which is likely why the answers reflect that.

Also, people (men especially i think) are wired to see the problem and offer a solution before they have heard everything. That's the way we think. So I know I have often been guilty of not reading everything and just chiming in with a solution. Just as I have likely cut my wife off in mid-sentence many times with an answer before I have even heard the entire question.
 
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Old 01-22-21, 06:48 AM
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Oops! I was looking at the picture and "did not see the pipes there yet" I thinks to meself, are the pipes out of sight behind the wall in the outside world? I have seen pipes attached to the surface of the outside wall in warmer climates. Today I look again and what I thought were red and blue electrical cables were the pipes! Duh!
 
 

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