Insulating a shed floor

Old 11-09-05, 10:52 AM
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Insulating a shed floor

I am starting to build a 12 x 16 shed. It will have treated floor joist and flooring. I am going to heat and cool this building and would like to insulate the floor. The problem is one side of the shed will only be 4" off the ground so it would need to be insulated after the floor joist are built and before the plywood floor is installed.
I have thought about buying some of the black material that is used under mobile homes and attaching it to the underside of the joist. This material would hold the insulation in place and keep animals from tearing out the insulation.
Does anyone have any thoughts or better ideas on this?
Old 11-09-05, 11:28 AM
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You'll need to apply 1x2 strips to each side of your floor joists. The bottom edge of the 1x2 will be even with the bottom of the floor joist. Then you'll need to drop in some 1/2" plywood, ripped 14 3/8" wide so as to fit between the floor joists. If you prefer, you can caulk the edges of the plywood so as to ensure you keep bugs and air out. Once you tack the plywood down, you'll be ready to lay your insulation in place.

The only problem with this is that the plywood will be exposed to the soil under your shed, which isn't good. You could use an exterior grade marine plywood... or you could paint the plywood prior to installation... and it would probably be a real good idea to lay down a piece of heavy plastic so as to cover the ground and act as a sort of vapor barrier. It'll keep weeds down too.
Old 11-13-05, 07:09 PM
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Where I'm at, a bldg. permit would be required to build the shed you are talking about. First, because it's more than 120 sq. ft., and second, because it's conditioned (heated and cooled) space. With a permit, you would have to have 18" of clearance between the dirt and the framing of the floor. You would be well advised to check with your local bldg. dept. before proceeding.

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