Insulation, Radiant and Vapor Barriers - Cold Floor

i have an addition that has a cold floor. the addition is about 3.5 ft above grade. the rafters underneath have bat insulation stuffed between. the elements are kept away because it is all enclosed by plywood but the floor of the addition IS above exposed soil.

is this standard? should i check/replace the existing insulation and/or enclose the exposed floor? will this affect the cold floor in the additional room. the room is 16x12C:\Personal\House\Addition.jpg

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This room has a higher heat load due to the exposed floor so thats why its cold. Air infiltration into the insulation even if covered with plywood can also be a strong possibility which will severely reduce the R value of fiberglass. How thick are the batts and do they totally fill the floor joist space? Was the floor and rim joist of the addition caulked/foamed and sealed against air infiltration before the batts where added? What kind of heating system do you have and if forced air is there a return?

Air leakage is probably a factor but not the major factor for your cold floor. The exposed soil below the floor is extracting heat from the crawl space. The solution is to cover the soil with a moisture barrier, 6 mil plastic of more to prohibit evaporation.

i have an addition that has a cold floor. the addition is about 3.5 ft above grade. the rafters underneath have bat insulation stuffed between. the elements are kept away because it is all enclosed by plywood but the floor of the addition IS above exposed soil.

is this standard? should i check/replace the existing insulation and/or enclose the exposed floor? will this affect the cold floor in the additional room. the room is 16x12http://images.kodakgallery.com/photos3922/5/69/41/1/13/3/313014169505_0_ALB.jpg

Addition
http://s267.photobucket.com/albums/ii320/Darkman3230/?action=view&current=Addition.jpg