Insulating Under floor over concrete

Vinchenzzi · #1 Sep 21, 2009, 01:09 PM

I have a raised living room 2 feet over a concrete slab which was once a garage. They never insulated the floor and in the winter the floor gets extremely cold. I was thinking about renting a blown in insulation machine and filling in the entire void with fiberglass ins. Can anyone tell me if this is a good or bad idea and if the there is a better one. Taking the floor up is out of the question and there is only about 6 inch's of clearance between slab and bottom of floor joists so crawling around is out as well. I have an acces where the stairs go up into the living room from outside and that's it so figured blowing it in would be easy but was unsure about moisture and stuff. will be home in 2 weeks and ready to tackle so need some ideas. Thanks

Cedarln2265 · Sep 21, 2009, 01:14 PM

If you are a Senior Citizen new gov't program tohave workers do the insulation is available. Also need more details, age of house, is electrical wiring under house and water/gas pipes. Only asking since you wrote that floor is above slab

Vinchenzzi · Oct 15, 2009, 04:51 PM

There are no pipes for water and there is only cable lines under there that I ran. As I said in my original post, it was once a garage that was converted into a room with cathedral ceilings. The floor of the room is elevated 2 feet to be even with the other floors of the house. So Can fiberglass ins. be blown in on top of the concrete. Will there be problems with moisture or some other problem. The house is 50 years old but the addition is 15, not sure if that matters but there it is.There has to be someone out there who can answer this. So far I have asked 3 questions and Have been un successful in getting an answer for any of them, this is a challenge for all u experts.

Vinchenzzi · Oct 15, 2009, 07:59 PM

I will be able to see the insulation being blown in , you are correct in that there are floor joists but I can see under them and the new insulation is expandable. As far as the vapor barrier I would say probably not. Will the Moisture and mold be that bad, as of now the floor in the room gets quite cold and since my options are limited I'm in a bind.I will be able to get the insulation hose all the way to the back using a swimming pool extendable pole so I believe I can get it in there fairly evenly. I will await another resonse

pattyg2 · Oct 17, 2009, 04:42 PM

You need to know if there is a vapor barrier installed under the floor. It should be felt paper on top of the concrete. If there is felt paper then you can try to blow insulation in. If there is no vapor barrier then no and I would think about putting one in.

microllins · Nov 1, 2009, 12:59 PM

You may be better off having CLOSED CELL polyurethane foam injected into the cavity. It has better R-value, and is a moisture barrier, depending on the density.