I'm doing some siding repair right now and just pulled the lower 20" of siding off of a wall. One of the things just behind it is a PVC drain pipe someone ran inside the wall. This drain has frozen multiple times in the past.
While I have the wall open, what's the best way to insulate this pipe against further freezing? Should I use the expanding foam stuff? Or just get the best fiberglass batt I can find? What was there before was some yellow fiberglass insulation and then 1" of styrofoam and then 5/8" of T-111.
There was all kinds of rot and holes at the bottom of the T-111 (which is why I'm replacing it) so there were plenty of air holes to expose it. Presumably it will be better with new siding.
There is some expanding foam insulation between a couple other studs and I think that's protecting the laundry drain and possibly feeds too.