Pipes on Outside Wall


  #1  
Old 01-20-21, 07:49 PM
G
Gen
Gen is offline
Member
Thread Starter
Join Date: Jun 2006
Location: US
Posts: 793
Received 16 Upvotes on 11 Posts
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.


 

Top Answer

 
01-20-21, 08:12 PM
PJmax's Avatar
PJmax
PJmax is offline
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 64,816
Received 3,922 Upvotes on 3,518 Posts
Yes.... PEX is more forgiving but no one with common sense puts plumbing in an outside wall in a cold zone.
 
  #2  
Old 01-20-21, 08:12 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 64,816
Received 3,922 Upvotes on 3,518 Posts
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.
  #3  
Old 01-20-21, 08:22 PM
XSleeper's Avatar
Group Moderator
Join Date: Dec 2004
Posts: 27,045
Received 1,905 Upvotes on 1,711 Posts
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.
 
  #4  
Old 01-20-21, 10:50 PM
Marq1's Avatar
Member
Join Date: Sep 2016
Location: USA MI
Posts: 9,745
Received 1,210 Upvotes on 1,098 Posts
Just confirming, is that a basement wall?
 
  #5  
Old 01-21-21, 05:15 AM
Norm201's Avatar
Member
Join Date: Sep 2013
Location: United States
Posts: 10,956
Received 721 Upvotes on 640 Posts
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.
 
  #6  
Old 01-21-21, 05:34 AM
G
Gen
Gen is offline
Member
Thread Starter
Join Date: Jun 2006
Location: US
Posts: 793
Received 16 Upvotes on 11 Posts
Thanks for the replies. It's not a basement wall, nor are they 2 x 6 studs...
 
  #7  
Old 01-21-21, 05:40 AM
Norm201's Avatar
Member
Join Date: Sep 2013
Location: United States
Posts: 10,956
Received 721 Upvotes on 640 Posts
Before they close up that wall I would reroute the plumbing.
 
  #8  
Old 01-21-21, 05:48 AM
XSleeper's Avatar
Group Moderator
Join Date: Dec 2004
Posts: 27,045
Received 1,905 Upvotes on 1,711 Posts
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.
 
  #9  
Old 01-21-21, 05:53 AM
G
Gen
Gen is offline
Member
Thread Starter
Join Date: Jun 2006
Location: US
Posts: 793
Received 16 Upvotes on 11 Posts
Unfortunately, It's not quite my job to dictate on this X...I'm just an out side observer.
 
  #10  
Old 01-21-21, 06:03 AM
Norm201's Avatar
Member
Join Date: Sep 2013
Location: United States
Posts: 10,956
Received 721 Upvotes on 640 Posts
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.
 
  #11  
Old 01-21-21, 07:45 AM
G
Gen
Gen is offline
Member
Thread Starter
Join Date: Jun 2006
Location: US
Posts: 793
Received 16 Upvotes on 11 Posts
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.
 
  #12  
Old 01-21-21, 08:59 AM
XSleeper's Avatar
Group Moderator
Join Date: Dec 2004
Posts: 27,045
Received 1,905 Upvotes on 1,711 Posts
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%.
 
  #13  
Old 01-21-21, 09:15 AM
C
Member
Join Date: Mar 2007
Posts: 2,503
Received 350 Upvotes on 293 Posts
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.
 
  #14  
Old 01-21-21, 09:34 AM
Norm201's Avatar
Member
Join Date: Sep 2013
Location: United States
Posts: 10,956
Received 721 Upvotes on 640 Posts
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.
 
  #15  
Old 01-21-21, 10:50 AM
A
Member
Join Date: Mar 2010
Location: USA
Posts: 4,515
Upvotes: 0
Received 276 Upvotes on 252 Posts
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.
 
  #16  
Old 01-21-21, 10:58 AM
XSleeper's Avatar
Group Moderator
Join Date: Dec 2004
Posts: 27,045
Received 1,905 Upvotes on 1,711 Posts
And you shouldn't conceal pipe wrap inside a wall. Ask any fireman.
 
  #17  
Old 01-21-21, 06:31 PM
G
Gen
Gen is offline
Member
Thread Starter
Join Date: Jun 2006
Location: US
Posts: 793
Received 16 Upvotes on 11 Posts
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.
 
  #18  
Old 01-21-21, 07:20 PM
XSleeper's Avatar
Group Moderator
Join Date: Dec 2004
Posts: 27,045
Received 1,905 Upvotes on 1,711 Posts
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.
 
  #19  
Old 01-22-21, 05:48 AM
A
Member
Join Date: Mar 2010
Location: USA
Posts: 4,515
Upvotes: 0
Received 276 Upvotes on 252 Posts
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!
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: