Seeking advice on insulating a floor from the crawlspace below.


I have to insulate the floor in an older ranch house. It will be done from underneath, which is a crawl space. (Ugh.)
Anyway, considering the usual array of pipes, electrical wires, and cross-bracing between the joists that all tend to make the job more of a hassle, what would be the most workable type of insulation to get? I thought about rigid, but it would mean a lot of cutting and fitting.
If it turns out to be batting, that means the paper side would be facing the ground. Is that OK?
Any other tips on how to do this are very welcome.
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kimosabe wrote:

blown on foam? not a diy project, these are usually truck mounted. getting at the pipes afterwards would be a HASSLE though.
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If you can afford it, have a professional spray urethane foam.
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Robert Neville wrote:

Will any responsible professional spray urethane under a house, where it won't be completely surrounded by highly fire resistant material?
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I just glued high density foam board to the inside of crawl space walls. My place has forced air ducts in the crawl space. The heat loss from the ducts stays in the crawl space and helps keep the floors warm.
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TheHack wrote:

And we have a winner! If your crawl stays dry, and the sidewalls get down or close to frostline, insulating the walls is the way to go. Link to that free ground heat and cooling.
--
aem sends...

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You would just be increasing the amount of space you are heating and cooling.
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JimT wrote:

The delta from the 55 degree ground temp of a well-insulated 'finger' of earth temp touching the bottom of your heated envelope, is small. Same concept is an earth-bermed house. No HVAC ducts feeding the crawl, of course. I'd only try this on a deep dry crawl or basement where I could heavily insulate the walls, though. And in summer, of course, when it is a bazillion degrees out, that cool slab or covered dirt is already keeping the floor above halfway cool.
That dream house I'm gonna build when I hit the lotto? - deep basement with thick walls insulated on the outside to below frostline. Even if furnace goes out, should stay above freezing in winter, for several days. There is a reason bears hang out in caves over the winter.
--
aem sends....

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I've lived in upstate NY for 56 of 60 years. Back in 1970 the Marines sent me to the balmy climes of the Chesapeake Bay in VA. We arrived in Sept, and by mid Feb I was certain I'd never leave VA. My young bride and I walked on a deserted beach on Christmas day. . . I hunted boar that winter in shirtsleeves in the mountains to the west.
Then summer came. I can take the cold. I can't take the heat. I was happy to get back to 4 distinct seasons in 1972.
Maybe when I'm 80 I'll feel more inclined to leave the north-- but for now, if I hit the lotto, I might build a cabin in Maine, and another in Key West-- but I'll *live* in NY.
Jim
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Not nearly cold enough in the winter for me. The summer temps look good, but I want real winter.
Cindy Hamilton
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Let me Google that for you. :-)
This one shows a generous crawl space but you get the idea.
http://videos.howstuffworks.com/johns-manville/1924-how-to-insulate-a-vented-crawl-space-video.htm
Jim
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It would appear you have 2 choices..Either fiberglass bats or spayed foam...If you can afford it foam is best...If not fiberglass is your only choice...On a happier note you could have it installed by an insulation contractor for about what you would pay for it retail...Atleast around here..(Maine) My garage doors were the same...I got them installed by a garage door company for about 100 bucks more than I could buy them...FWIW...
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kimosabe wrote:

Do NOT use foam board, spray foam, or anything else flammable. Stick with fiberglass or rock wool.
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kimosabe wrote:

Call up the utility companies and local conservation organizations, not to be confused with for-profit weatherization contractors. Depending on where you live, there are GENEROUS weatherization incentives and rebates available...and I do mean GENEROUS, as long as you comply with their requirements. That may dictate the type of insulation you choose.
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