1885 Victorian mix of 2 pipe and 1pipe radiators all with vents

Johnny_D

What thickness is recommended? Assume it reduces from near piping > mains > returns.

Double D

One inch thickness is recommended unless the pipe passes into non-conditioned space such as attic or crawl space.

nicholas bonham-carter

Make sure it is fiberglass insulation, at least 1 inch thick. Foam rubber will be a sticky mess!!
You could skip covering the elbows for now, and do them later.—NBC

Johnny_D

Need help with liner:
https://forum.heatinghelp.com/discussion/167522/liner-wont-reach-the-basement-in-old-victorian/p1?new=1