Spray foam insulation to prevent condensation? (1st post)

ajmckay

Hello everyone. The forum comes up a lot in my search results on various topics, so I figured I should join and contribute some as well !

Anyways, I'm remodeling my kitchen and while I have the drywall out I noticed that the water supply line (copper) going to the toilet on the other side of the wall is pretty corroded (the house is 40 yrs old). I've also noticed what looks like a little bit of water staining on the sill plate it comes up through from the basement. The pipe itself doesn't seem to be leaking.

Part of the problem is that they used steel clamps to hold the pipe down (which I will replace with copper or plastic), but I'm thinking that the other problem is that the pipe is uninsulated and it's getting wet from condensation during the summer.

I was thinking of slipping some pipe insulation over it, but it's located right against a wall stud, so I can't get the insualtion to really cover the pipe.

So here's my question: Do you think it would be alright to cover the portion of copper pipe that's in the wall (maybe 8-10" total) with spray foam insualtion to prevent condensation?

Thank you!

ajmckay

So no thoughts? Or is the question just absurd?

Here's my thought process:
- The pipe is definitely attracting condensation. I think that the proof is in the rust on the steel pipe holders (which are getting replaced with plastic) and the obvious stains on the wood right next to the pipe. It's also pretty evident when you look at the toilet. After flushing, the whole outside of the toilet attracts condensation! This is an interior wall, though it is perpendicularly connected to an outside wall. There is no insulation in the stud cavity.

- I think that somehow insulating the pipe would be a good idea to minimize the amount of warm air that can get to the cold pipe and cause condensation.

- I'm thinking, however, that spray foam may not be the best because it would completely seal in any condensation that does form and potentially cause issues. As I understant it moisture and heat can pass through wood pretty easily, so if I seal up one side of the pipe with spray foam is it possible that moisture accumulates right up against the wood and causes rot?

- I can half insulate it with some of the black foam pipe insulation, but it's difficult to get it secured to the pipe.

- My other thought is to slide a sheet of plastic in-between the pipe and the wood stud and then use the spray foam. The objective being to separate the pipe from the wood so that if condensation does form hopefully it doesn't sit up against the wood. The only downside of this way is that if condensation forms at all it won't have anywhere to go...

So maybe the right choice is to just leave it be and hope that as condensation forms it just evaporates as it has for the last 40 yrs?

TheEplumber

I'm not a fan of spray foam touching my pipes. I'd put blanket insulation in

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ajmckay

Thanks for the reply eplumber.

Spray foam is pretty sticky stuff I know! The more I think about it the more I'm thinking that the spray foam probably isn't the best idea. Of course my mind can change many times in this sort of situation though, so I really do appreciate your suggestion.

In-fact, I think I'll do that. I'm going to half insulate the pipe with foam pipe insulators and then put in fiberglass insulation in the stud cavity.

I think this solution should help at least minimize the condensation. At the very worst, I wouldn't expect it to make it any worse than it was before!