Thursday, October 1, 2026
Q. We just got over a lot of repairs from a burst pipe under our kitchen sink. The pipes under the sink are back in the outside wall, with insulation around them, but I’m wondering why they said it was still a good idea to let the water drip, even run a little when it gets cold out. It seems wasteful, and I wasn’t sure why they told me that. Is it because they’re not confident in the repairs, or does everybody have to run their water in the winter when pipes could freeze?
A. The work was not repaired correctly and should be redone before it gets too late to get anybody to return to the “scene of the crime.” Water freezes, and supply-line water that’s buried in outside walls and not kept warm will turn to ice.
Several years ago, a client, who had work done in the summer, called the following winter to say he had no running water in his bathroom sink. The sink was on an exterior wall, but the rationale the installers used for where they put the insulation was that a roof from below came up to meet the outside wall behind the sink. They told the owner that the roof protected the pipe because of how far the sink was set in from the walls below, set back the way it was designed.
They cut open the back of the finished sink cabinet and exposed the pipe, telling the owner that he just needed to let the water trickle and keep the cabinet doors open all the time in the winter. I was called after they told the owner that was a bad design. He was very frustrated by the time we spoke, because the plumber and contractor had already returned several times and this was their final answer.
The simple solution, which worked for him and will work for you, is that supply pipes need to be to the warm side of insulation. I saw that the cold- and hot-water supply pipes were completely enclosed with insulation. I removed the insulation from the warm side and only kept the full thickness of insulation on the cold side. The roof cavity behind the wall, in drawings that are called building sections, showed that the roof was to be insulated directly behind the wall to create a full barrier of insulation. Because there was now a gaping hole at the back of the cabinet, sloppily cut, I was able to peer in with a mirror and see that there was no insulation in the roof space where it met the wall behind the sinks. None. Once the water supply lines were moved into the cabinet, under the sink, by the plumber, who fortunately did stand behind their work and did return, there was never a problem again.
Locate pipes neatly in the back of the sink cabinet, to the warm side of a fully insulated wall and there should be no more problems. Good luck!
© 2025 Monte Leeper. Readers are encouraged to send questions to yourhousedr@aol.com, with “Herald question” in the subject line, or to Herald Homes, 2 Endo Blvd., Garden City, NY 11530, Attn: Monte Leeper, architect.
