# Insulating Pipes in a crawl space



## drewdin (Oct 30, 2013)

I'm going to insulate the hot water lines in my crawlspace, at the box stores they have a rubber insulation and a fibreglass insulation for 3/4" copper. My question is which one is better and why?

I asked the Guy at Lowes/Depot and I might as well have asked the wall. Thanks


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## nealtw (Oct 30, 2013)

All foam is not equall but I think some have a higher R value than FG just keep it 10 inches away from heat like furnance flue. Fibre glass is used for higher temp, steam pipes and such. I would do both hot and cold for the condension in summer.


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## drewdin (Oct 30, 2013)

Thanks Neal, I actually planned on using the foam covered by FG, just for the Crawlspaces. Might be overkill but i wanted to make sure it was warm no matter what! Thoughts?


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## nealtw (Oct 30, 2013)

It's not really expensive I don't see why not.


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## eddietheplumber (Oct 31, 2013)

drewdin said:


> I'm going to insulate the hot water lines in my crawlspace, at the box stores they have a rubber insulation and a fibreglass insulation for 3/4" copper. My question is which one is better and why?
> 
> I asked the Guy at Lowes/Depot and I might as well have asked the wall. Thanks



Hot water lines sweat if u use the fiberglass it will soak up the sweat and can get wet enough to freeze in the winter.if u use rubber it in my opinion drys better and as long as u tape the bends also u will b fine


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## nealtw (Oct 31, 2013)

Eddie; Welcome to the site, not sure why a hot water line would sweat. Cold lines sweat because the water cools the pipe and then the pipe cools the surrounding humid air. As the air cools it deposites the water on the pipe.


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## drewdin (Nov 24, 2013)

I was talking with some Insulation guys at a plant the other day. They were telling me to use rubber on cold water and fiberglass on hot water pipes. The reasons being that the hot water pipes go from hot to cold when being used or during winter, etc.. The heat change will cause the rubber to dry out and over time crack and crumble.


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## nealtw (Nov 24, 2013)

I always like it when people have a good story that you can beleive until you find out they are full of it.
http://www.leaningpinesoftware.com/hot_water_pipes.shtml


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## drewdin (Nov 25, 2013)

@neal, i guess what I wanted to do is the preferred method and the insulation guys were right except for, only high temp systems like steam will deteriorate the rubber but its fine for anything else. Great article, thanks!


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## nealtw (Nov 25, 2013)

I found the part about hot water usage interesting.


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