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Copper water line insulation.

Snowbird13

Snowbird13

Well-known member
Joined
May 25, 2020
Member Number
1371
Messages
164
Loc
Oregon
What's the proper way to insulate copper water lines inside an insulated wall? The water lines for my water heater run from my garage in to the wall, then from there down into the crawl space. Lines are sweating (condensation) causing the sheetrock and insulation to mold. House was built in 96.
 
seems wierd that it would find enough airflow to condense moisture in the wall

I'd toss some of that armaflex closed cell foam rubber pipe insulation at it (the kind with the double sided tape at the cut)
 
you sure your vapor barrier is like sealed up good?
it really shouldn't be seeing that much airflow
 
[486 said:
;n247747]you sure your vapor barrier is like sealed up good?
it really shouldn't be seeing that much airflow
Click to expand...

Vapor barrier where?
 
More info. There was a 2x6 running horizontal between the studs. Im assuming to stop water hammer?. Completely rotted out, as well as one of the studs it was attached to. I can see some daylight coming from the garage where the expanding foam failed
 
Are the holes where the lines come in through the crawl space sealed? I had an old home that had actual vents built into the house to keep the airflow moving in the crawlspace but by 96 I don't think that was code.
 
Pony_Driver said:
Under your siding and outside the sheathing.
Click to expand...

Attached garage. Hot water heater in garage. Bedroom on the the other side of wall that I noticed the mold in. Garage side is plywood attached to studs with sheetrock on top of that
 
Pony_Driver said:
Are the holes where the lines come in through the crawl space sealed? I had an old home that had actual vents built into the house to keep the airflow moving in the crawlspace but by 96 I don't think that was code.
Click to expand...

There is expanding foam in the holes, yes.
 
Snowbird13 said:
Attached garage. Hot water heater in garage. Bedroom on the the other side of wall that I noticed the mold in. Garage side is plywood attached to studs with sheetrock on top of that
Click to expand...

Garage = unconditioned space. That might be the source of the moisture.
 
The hot water line is sweating? That's not an insulation problem, that's a leaking line somewhere.

Sweating is only going to happen if significant warm humid air hits something cold enough to cause condensation. Summer time in the south I could see it being an issue on domestic cold water lines, but not in the winter, and not in OR. Plus, if it's a hot water line the line would be warmer than surrounding air, not colder. Beyond that, there shouldn't be enough airflow in the wall for significant condensation to happen in the first place.

I'm willing to bet you have a leaking fitting(s) and it running down the pipe.
 
sdmuleman said:
The hot water line is sweating? That's not an insulation problem, that's a leaking line somewhere.

Sweating is only going to happen if significant warm humid air hits something cold enough to cause condensation. Summer time in the south I could see it being an issue on domestic cold water lines, but not in the winter, and not in OR. Plus, if it's a hot water line the line would be warmer than surrounding air, not colder. Beyond that, there shouldn't be enough airflow in the wall for significant condensation to happen in the first place.

I'm willing to bet you have a leaking fitting(s) and it running down the pipe.
Click to expand...

I think you might be the winner. If I run the hot water, there is a tiny bit of moisture around the copper elbow. So I have no idea how to do copper.

Shark bite to pex?
 
Run a test and see if it only leaks when the hot water is run. You can sweat new fittings on if you need to replace it. Just use flux. Or go the sharkbite route if you want to be quick about it.
 
Snowbird13 said:
I think you might be the winner. If I run the hot water, there is a tiny bit of moisture around the copper elbow. So I have no idea how to do copper.

Shark bite to pex?
Click to expand...
They do make shark bites that go from copper to Pex, but IMO you're better off sweating in a copper elbow.

I just used the pipe insulation 486 recommended for all my copper lines in my unheated crawlspace. I haven't had any freezing issues in the 8 years since I've done it and I live where it gets cold in the winter.
 
didn't see where it was the hot line and not the cold feed
yeah hot lines don't sweat
they do seem to corrode through a lot quicker though for whatever reason
 
Snowbird13 said:
I think you might be the winner. If I run the hot water, there is a tiny bit of moisture around the copper elbow. So I have no idea how to do copper.

Shark bite to pex?
Click to expand...

No skills? This is the fitting for you. You still need to use wire brush to shiny up the pipe outside diameter, and the inside diameter of the elbow. You also still need to use flux on both parts. Stick this on and heat until you see a nice solder ring.

They`re fuckin beautiful. Called a solder ring elbow.

Click image for larger version Name: copper elbow.jpg Views: 0 Size: 41.3 KB ID: 247832
 
if you've got oxy-fuel torches, hard solder is a lot easier than lead, what with no flux, no cleaning and no upper limit on temperature
get you a stick of dynaflow and use that
 
Never messed with copper before. Do I heat up the old elbow to take it off? If I cut it off, then i would need to lengthen the lines, correct?

Also, would prefer not to catch my house on fire.
 
Last edited:
You can drain the line and sweat the old piece off. From there clean the old ends with a wire pipe cleaner or emery cloth, FLUX both pieces and sweat the new elbow in. The elbow someone posted above has the solder already in it. It's not difficult to do, check youtube for examples. If you are super concerned about fire keep an extinguisher on hand. I had a plumber come in once for a broken hot water line and he asked for windex. When I asked him why windex he said "Most everyone has it on hand". He sprayed the wall cavity with a couple of squirts after soldering in a line. It was probably not necessary, but that's what he did.
 
Pony_Driver said:
You can drain the line and sweat the old piece off. From there clean the old ends with a wire pipe cleaner or emery cloth, FLUX both pieces and sweat the new elbow in. The elbow someone posted above has the solder already in it. It's not difficult to do, check youtube for examples. If you are super concerned about fire keep an extinguisher on hand. I had a plumber come in once for a broken hot water line and he asked for windex. When I asked him why windex he said "Most everyone has it on hand". He sprayed the wall cavity with a couple of squirts after soldering in a line. It was probably not necessary, but that's what he did.
Click to expand...

Since OP is copper dumb......sweat means heat it up until the solder is melty.
 
Snowbird13 said:
I think you might be the winner. If I run the hot water, there is a tiny bit of moisture around the copper elbow. So I have no idea how to do copper.

Shark bite to pex?
Click to expand...

Do the shark bite fitting to PEX for the repair... if you haven't ever soldered copper pipe, it's going to be sucky for ya.
 
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