cold climates: insulating floors w/plumbing above cold crawlspaces

I run into this all the time.
Typical scenario…
In Colorado where the winters are cold, the floor above the crawlspace is uninsulated. The foundation walls are leaky and the home loses a lot of heat into the crawlspace… that’s what keeps the plumbing pipes hanging from the floor joists from freezing since there’s no means of heat distribution through the crawlspace.
Clients want to know if they should insulate the floor to save on heating costs. Well, saving on heating costs is always a good idea.
“How do I keep the pipes from freezing?” they want to know. Heat tape can help, but it’s electrical and in the mountains, when it gets real cold, sometimes we lose the electricity for a while. Sometimes for days. If you happen to be gone and your electric heat tape is all that stands between you and a big bill for a flooded home… you’ve got a potential problem.

I ask local plumbers about this and they just roll their eyes. Any suggestions?

We don’t have too many freezing days or night here but on occasion we do. Typically what I see is foam coverings (one brand name is “Armaflex”) that comes in 6 foot lengths and is relatively inexpensive. Cuts easily for miter joints and even has some special glue to seal the joints and seams. Also this is an article written for this Old House show.,26206,1191783,00.html

I recommend closing off all vents, insulating the perimeter walls, install plastic on the floor (ground) and stick a heat duct or two down there. I’ve done this for years arounf here and it works great.

Ditto. This is what I did in my house in Iowa.

We’re talking 20 below so foam pipe wrap won’t really do it. I think Larry’s right. The problem is that a lot of these are stone rubble foundations and hard to insulate. I guess you could just lay fiberglass batt against them. These are usually low-end homes.

20 below! We rarely see 20 degrees above zero. Sounds like maybe you need heat strips or something mechanical to keep them from freezing. Hope you work it out. Sorry I was no help.

Doug, foam pipe wrap is a good suggestion and I recommend it often, just doesn’t quite do the trick in this particular situation.