Frozen pipes in exterior wall

27 days ago

We’re having extended periods of single digit and below-zero temps here in the NE right now. Our second floor shower is freezing up because it runs up through an exterior wall. The bathroom is above our unheated garage, but we put in foam insulation, R-60 on the finished ceiling and a bit less in the walls. It stays about 40-50F.

The pipes (PEX) run up through a wall shared with the interior of the house, across the garage ceiling (and under the bathroom floor) and up through the exterior bathroom wall, which we also insulated with foam. That wall is cedar clapboard on the outside and tile on the inside and is the only part of the plumbing run that is not adjacent to finished living space. The bathroom floor above the garage is also heated if it matters.

I’m thinking we could open the garage ceiling sheetrock and put heating tape on the pipes for some distance. It would not go up into the wall, but I’m thinking it might be enough to warm the pipes and prevent freezing. Does this sound like it would work? thanks.

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Comments (6)

Stax
27 days ago
In the short term, turn the shower on and let the water run slowly all night and day.

Depending on how the insulation was installed in the wall containing the shower head, the insulation might actually be exacerbating the situation.
Joanne
Original Author
27 days ago
Thanks, we have been letting the shower run at a fast trickle, but on the coldest of nights, it still froze up. When the sun comes around to that side of the house in the afternoon, it warms up the wall and the water starts running again.

Before we remodeled the bathroom, the wall had some fiberglass batting in it. The contractor put fiberglass back in and closed it up. The second winter, we had freezing for the first time, and we had the exterior wall opened up and foam put in to prevent the problem.

Because we like the bedroom cool, we don’t run the boiler for that zone much. I put in a wall mounted programmable convection heater to keep the bathroom warmer than we would like the rest of that area. This is the wall before it was closed up and tiled.
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klem1
27 days ago
Pex doesn't conduct heat the way copper and iron does so heat tape would only protect the line where it's in contact. If the garage never falls well below 32*f , heat tape in ceiling would serve no purpose. I think the problem lies in what Stax mentioned about improper installation of insulation. In simple terms after wall in the picture was insulated the water lines would still be visible, ditto for any exterior wall.
Joanne
Original Author
26 days ago
Would keeping the room extra warm help? There’s nothing I can do about the tile side of the wall as far as I know, but I would consider opening up the siding again if necessary. I’m assuming that you can’t bury heat tape inside a wall so there may not be a point to doing that.
klem1
26 days ago
Without being there to inspect, I'm not going to recommend drastic measures like removing siding. I don't know what,where and how plumbing and insulation was done, therefore can only tell you what is common practice.
PRO
Joseph Corlett, LLC
26 days ago
No heat tape on interior walls please.