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HeyPally 01-25-2009 09:48 AM

Framing/Insulating around water supply pipe
I'm currently renovating my basement in an 80+ year old house. The basement is fairly low (just over 6') but it's a good useable space that I want to finish nicely. I've recently had an interior weeping system installed due to water issues which has a plastic membrane going 4' up the foundation wall. As I'm framing the walls I've realized that the incoming water supply pipe runs along the bottom of the joist along the front wall of the house. Because of the interior weeping system I cannot frame right to the foundation wall. I need to leave approx. a 2 1/2" gap between the framing and the wall. My question is I want to avoid a cold space around the water supply pipe, but since it runs directly beside the foundation wall and I am framing 2 1/2 " away from the wall, how can I insulate around it to ensure there is no freezing issues?

I hope I've explained myself well enough...Thanks in advance for any advice!

glennjanie 01-25-2009 07:50 PM

Welcome HeyPally:
Check with the local pluming/ heating supply house and ask for closed cell foam insulation, one brand name for it is Armaflex. There is one company that makes the foam with a slit down the length of each piece with wax paper in the cut; pull the wax paper out and press the foam togather for permanent gluing. The glue is already in place.

HeyPally 01-26-2009 10:03 AM

thanks glennjanie,

I had thought about using this but wasn't sure if that would be sufficient enough if the pipe will be in the "cold space" behind the insulation. It will make my life a whole lot easier if that will prevent any freezing on these wonderful -15 degree Celsius days :)

glennjanie 01-26-2009 11:33 AM

Hello HeyPally:
I would like to make another point about insulation. It doesn't keep the pipes warm; it only protects the heat in the pipe and temporarily holds it there. The R-rating on insulation tells you how quickly the heat will travel through the insulation.

So, if the water stays still in the pipe that is insulated, it will eventually give up enough heat to freeze. In your case letting the water run a very small stream (with the insulation) through the night should keep the pipe from freezing.

You may also want to consider a single strand of heat tape inside the insulation. There is a heat tape now that has its own thermostatic control the full length of the tape. If a one or two foot section gets too cold it will warm itself up in that area only. With the heat tape inside the Armaflex you would be secured.

HeyPally 01-26-2009 02:39 PM

Thanks, Glenn.

The heat tape is a possible idea. I'm also considering using rigid insulation above the waterproofing membrane up to the pipe and then spray foam insulation in the very slight gap behind the pipe. Then again use the foam board in front of the membrane. I would then just frame in front of it. My issue with that though is I would need to use adhesive to "stick" the insualtion to the wall since I don't think it's a good idea to put screws in the concrete block and the waterproof membrane. Do you think there's any issues with this method? I'm guessing it would avoid any cold areas where the pipe would be.

glennjanie 01-26-2009 04:55 PM

Hello HeyPally:
The method you have proposed would probably work. However, it seems very labor intensive in comparison and I would still use the heat tape, it won't use any eletricity unless the temperature drops below 36*.

Your are indicating that you will insulate the pipe from the indoor heat as well as the outdoor cold. Whichever way you choose to insulate the pipe, a heat tape will be the only 'trouble free' way to go.

HeyPally 01-26-2009 08:01 PM

Makes sense. I'll frame it away from the wall as I have done with the rest of the basement and use the Armaflex with the heat tape. Is that hard wired or plugged in? Thanks so much for your insight, Glenn. I really appreciate having a 2nd opinion on this.

glennjanie 01-26-2009 09:36 PM

Hello HeyPally:
If you can find the right supply store, they will cut the heat tape to length for you and sell you a 'dead end' and a cord attachment. You heat shrink them on and plug it up.

HeyPally 01-27-2009 08:26 AM

Perfect. Thanks again.

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