floor insulation


Old 01-11-03, 06:47 AM
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floor insulation

i have recently installed laminate flooring in my home and the floors always seem cold. the furnace runs more frequent now. i live in michigan and need to know if and what kind of insulation to install under the floors. i have a crawl space that is very assesable. any response would be appreciated. thanks
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Old 01-12-03, 10:13 AM
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Floor insulation

Go to www.doityourself.com/insulate on this website for an excellent tutorial on insulation. You will find a description of the different types of insulation and recommended applications. You will also find a calculator to calculate the R-value for your ZIP.

If you do not have insulation between the floor joists, rolled batt insulation works well between joists. If you do not have a polyethylene (plastic) vapor retarder over the soil in your crawl space, it might be a good time to install that after you install your insulation.
Old 01-13-03, 12:12 PM
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FG in a crawl space is a sure way to wind up with mold and condensation problems.

I have been installing radiant barrier (RB) insulation for 29 years and have developed a method that is superior to any other I've seen. It's easy to do too.

Make sure the space is well DRAINED.
Seal all air leaks and seal vents.
Remove any FG present.
Attachch a 4 mil plastic sheet to the side of the bottom plate and let hang down and across floor. Install remainig plastic over floor, overlaping seams 6". Install second 4 mil sheet acroos over the second.
Install a 4 mil, 48" RB to the side of the bottom plate over plastic. Let hang to floor.
Install RB sheet in between joists at rim board.
If you have really severe cold you can increase the eff by laying a RB over the plastic on the floor. No more problem.

If you have any trouble finding RB let me know. I can send you a sample and drawing.

Thank you for considering my opinion.
Old 01-13-03, 01:18 PM
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The only way that we have found over many many years has been. To seal all vents in the crawlway put a 4 or 6 mil poly down on the ground with a good over lap and up the wall about 12". A 2" polystyrene on the walls up to the joist. Then cut like blocks of R-19 FG and put them up in the joist space on the sill all around the home. If you have the duct work down there in the crawl cut in two small reg outlets and one small return . This sure works for us and will give you a warm floor.
Old 01-14-03, 12:21 PM
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The previous method using FG and foam is not as eff as RB. RB is about 95% eff, foam about 20% and FG less than 10%. Over 90% of the heat loss thru a floor is radiant. The RB is reflecting that energy back to the floor.

The FG will condensate and cause mold. Mold can also form behind the foam. Mold will not form on RB.

You have to take the vapor barrier up to the sill plate.

Thank you for considering my opinion.
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