[pete0403]

Hi, the wall in question is the lower wall on the right in the picture below. This part of the wall is below grade concrete slab and between the slab and the pictured stud wall is 2" XPS (R10) foamboard...there will also be R14 roxul in the stud space.

I want to run plumbing through this wall but was concerned about the rules against plumbing in outside walls. I can't imagine this section of the wall ever getting close to freezing tenperatures even in Ontario.

The other concern I have is that I won't be able to solder sections of copper together in-wall due to the flammable foam. I was thinking of just assembling the pipe, notching out the studs, and putting it in that way. The other possibility is PEX, which would be easier to install but is completely alien to me and I have none of the expensive tools.

Can I please get some opinions and advice on the two above points? Thanks very much!

The picture:

 

[brockmiera]

Is that a plastic vapor barrier you have over the XPS?

 

[mikey48]

Use pex and install it with the pipe inside (indoors) of the insulation. CPVC would also work.

 

[pete0403]

Is that a plastic vapor barrier you have over the XPS?

It just extends down a bit from the wall above.

 

[BC Plumber]

Pex is A LOT cheaper and faster to run, plus you will get better flow than copper if you have the ability to bend the pipe rather than put a 90 when required. Is there no other way to run the pipes than in the exterior walls? In Vancouver, where it doesnt get as cold as ontario winters, inspectors did not like to see any pipes run in exterior walls. Typically you don't run them in exterior walls unless you have to. When I did run pipes in exterior walls, I had to leave 3.5" from the wall to the backside of the pipe for the general contractor to double up the rigid insulation, or we had to use pipe insulation.

Are you doing this to rough something in or to run your mains?

 

[AllanJ]

Have no insulation between the pipe and the interior wall.

If you must use metal pipe and solder it, get piece of 20 gauge or thicker sheet metal of about one square foot area and curve it behind the place you are soldering. It should be at least an inch away from the pipe being soldered and extending at least two inches in every direction away from the entire area where you shoot the burner flame.

This way the flame won't touch the insulation and the sheet metal will spread out the heat.