Should I caulk around this drain pipe?

Question

I've got an interesting drain layout in the kitchen. Our water supply lines to the sink come up straight through the floor as is typical around here. However, the drain does not. It drops down and over at an angle and goes into the wall before dropping into the crawlspace. This is an outside wall, and I'm in a region that can see as low as -20 F during the Winter.

Currently, the drain pipe goes through a larger hole which is not caulked/sealed in any way. I'm sure I'm losing heat in the Winter because of that. However, I'm concerned that if I were to caulk around it that I might encounter freezing issues. Is freezing in drain pipes a thing to worry about at all?

Answer 1

You should seal that hole to keep vermin from passing through and to insulate. Any traps (the "u" or "p"-shaped drain fixtures that maintain a water-seal to prevent sewer gases from venting into your home) should be prevented from freezing, but those are usually located under the sink fixture outside of the wall. Some bathtubs and showers may be an exception to this, but in freezing locales these traps are usually placed in a location normally protected from freezing (like an interior wall or basement).