Plumbing runs on basement outside wall

n0c7

I want to run hot and cold PEX lines down a 2x4(wood) batt insulated "outside" basement wall to where my builder has roughed in a sink drain. I know that running plumbing in exterior walls above grade is usually not allowed but does this apply to the basement? If I'm allowed, what precautions do I need to take?

I live in a winter climate that gets very warm in the summer to sometimes arctic cold in the winter.

joecaption

Very bad idea, They should be if at all possible run down the center of the crawlspace and in your area I'd also insulate them with foam tubes.

n0c7

Sorry when I said outside wall I didn't actually mean outside. It's on the interior of the house foundation walls.

joecaption

Where are yu most likly to get air leaks in a crawl space?
Any cracks, gaps under the foundation plate, any vents. Moving cold air is what's going to freeze those pipes.

TheEplumber

When you drop into the wall, stay to the warm side of the insulation- against the drywall. Be sure the rim joist is insulated well.

n0c7

Here's a pic of what I'm working with:



Should the pipes be behind the vapor barrier or in front?

joecaption

In front

n0c7

Now that you've seen a picture - were we talking about two different scenarios?

n0c7

Local authority says in front of the vapor barrier but behind the drywall. Not sure how you clamp it down like this but hey.