how to insulate floor overhang

[jcannon11]

I have a 20'x2' floor overhang off the back of my house. During a recent cold spell, a small water line that is inside the house but back against the outside wall froze (did not burst). I can't access this line easily as a new kitchen counter was installed this summer (they mistakenly put this water pipe outside the cabinet and, as I said, next to the outside wall). So I went outside to see if I could insulate the flooring of the overhang. I found that it was insulated (fiberglass, probably 3" thick) and is covered with an aluminum 'siding' but obviously not enough to protect this small water line.

My question: how can I add more insulation to protect this pipe? I'm thinking of leaving the existing insulation as is and attaching a layer of styrofome (2" thick?) or fiberglass (R19?) insulation on the outside of the aluminum covering. Will this be OK despite the insulation (either one) being exposed to the outside (but not rain or direct sunlight), or should I look to remove the inadequate 3" insulation already there and replace it with some greater R value material (what would that be given the limited space available for insulation in the overhang floorboards?)?

Hope this makes sense. Thanks.

[HayZee518]

if there is no warm air flow in this section the pipe will just freeze anyway no matter how much insulation you stuff into the space. if this pipe was feeding water at a constant rate then you could install a heat trace tape to keep it above freezing - say a drip drip drip line.

[jcannon11]

The water line is from my sink to our new refrigerator (it has a door water dispinser). As I said, the line was put behind (rather than inside) our (also new) sink counter top so I can't access it without taking out some (?how much?) of the back of the counter. If I do that and put the line inside the counter space under the sink, and then insulate between the back sink counter wall and the outside wall (say with spray foam insulation - the stuff that hardens), do you think that will do the trick?

Since it's a line to the frig, I don't think a 'drip, drip, drip' will be possible (?).

Thanks for your help.


J.

quote:Originally posted by HayZee518

if there is no warm air flow in this section the pipe will just freeze anyway no matter how much insulation you stuff into the space. if this pipe was feeding water at a constant rate then you could install a heat trace tape to keep it above freezing - say a drip drip drip line.

[HayZee518]

you can try the foam insulation but my thought is that if the surrounding air temp is cold, the spray foam will get cold too and anything its around will be cold too. maybe a degree or two less cold because of the density of the foam.