Rerouting main water line inside house?

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Joseph Skoler

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Sullivan County, NY
I have a mid-1990’s manufactured home in zone 4 that I’m renovating.

It is built on a steel chassis/frame which sits on a concrete slab.

The crawlspace under the house (between the floor of the house and the concrete slab, where the steel frame is visible) has skirting, and the previous owner has put 2″ XPS rigid board behind the skirting to line the perimeter of the crawlspace.

The well water pipe comes up through the slab (sleeved in a 4″ PVC) and then traverses the width of the house through the crawlspace before going up into the house.

I see that the previous owner had it wrapped with heat tape, and had put an electric heater (the type that looks like an old fashioned water or steam radiator but it probably filled with oil and an electric resistance element for heat) in the crawlspace area to prevent that pipe (and maybe the drain pipes which are also in the crawlspace) from freezing.

I have the opportunity now to change the piping and have the well water pipe come (almost) straight up into the house, leaving only about 6′ of pipe exposed in the crawlspace (I can wrap heat tape and even build a rigid foam box around it for freeze protection).

By moving where the pipe enters the house I will have to run that pipe up through an interior wall, across inside the ceiling (on the interior side of the insulation) and then back down to where the pipe used to come in.

My concern (hopefully unfounded) is that the pipe would have condensation formed inside the walls and/or ceiling.

I know the very basics about condensation: Cold pipe surface makes the air touching it drop below dew point. I just don’t know enough to know if this is a concern in my case.

Should I put foam insulation on the pipe in the wall and ceiling (using 1″ Pex)?

Is this whole thing a good idea?

Thank you!

John Gayewski

In the Trades
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Thanks very much!

Making sure I understand: The pex pipe should insulated airtight? I got the 1-1/8" diameter pipe insulation, slit lengthwise with a continuous strip of peel off backing tape. I believe it is r-3.1 or 3.3.
Yes. Those sections of insulation should be glued together (or taped, but the tape sucks).
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