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Insulate under exposed floor

My house has what used to be a wooden deck behind the kitchen. At some point someone put sheetrock walls up and make it part of the kitchen/house.

The floor is about 4 feet above the ground. Nothing between the floor and the ground. During cold spells this part of the kitchen floor gets very cold.

I would like to put some insulation under it.

My thought was to put rolls and/or bats between the floor beams.

I'm wondering if this is OK. I'm thinking that I would want to cover the insulation with someting to protect it from the ground and whatever creatures are hanging around.

would I do this? What kind of material would one use? A plastic vapor barrier or some kind of sheetrock?

Re: Insulate under exposed floor

I had a similar problem with my house only it had to due with an addition that the previous owners had done. It included a family room and bedroom, below was a crawl of 3-4 feet. I used the fiberglass roll and covered with plastic for a vapor barrier to prevent mold and have had no problems since. Good Luck!!!:)

Timothy Miller
Re: Insulate under exposed floor

Howdy i would not put plastic on the joist but instead on the soil(6 mill) as you want moisture not to be trapped in the joist cavity can cause extensive rott and costly repairs... be sure to insulate the rim joist area and spray foam any gaps between the foundation and the framing as stoppin air infiltration will make the room above much warmer.

Re: Insulate under exposed floor

I stand corrected, after checking on the net I have found out that I was misinformed on the proper installation of the plastic and will have to fix mine. I also found a link to a crawl space dehumidifier, http://www.crawlspacedehumidifiers.com , Thanks Tim. :)

Re: Insulate under exposed floor

Never Never put plastic on the bottom side of the insulation.

To add to jkirk's post ............ you can also apply rigid foam sheets to the underside of the joists to cover the insulation ..... this will increase the insulation performance by also preventing thermol bridging.
If varmits are an issue then nail or screw plywood or OSB over the foam.

There are particular construction adhesives that can be used for foam boards like the PL300 foam board adhesive....... whicever brand used just make sure it's safe for foam board.

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