I want to insulate my floor in my house if i do so do i put up a plastic sheeting after i put in the insulate?
The plastic sheeting serves as a vapor barrier, and is needed only if your house is in a region where outside temperatures drop below freezing. The principle is that air inside of the house has moisture--from your breathing, from cooking, from the bathroom, and from your humidifier. Without the vapor barrier, the moisture will get into your insulation, which has a temperature gradient with the inside surface at room temperature and the outside surface below freezing. At some point within the insulation the moisture will freeze and ice will accumulate. This not only reduces the effectiveness of the insulation, but makes for a large problem in the spring when the ice melts. You can see that the vapor barrier should be against the inside wall, so that moisture can't get in the insulation. If you insulate your floor, the vapor barrier must go up. That is why it is best to use faced insulation, with the face up. Don't use plastic sheeting in conjunction with faced insulation, as moisture can get trapped between the two.
If you are insulating over a basement you do not need or want a vapor barrier. If you are insulating ove a dirt floor then the vapor barrier would face the unfinished part of the crawl space.
If you are insulating a ground level or below grade floor you need to build a frame from 2x2 strips and then fill in the spaces with styrofoam about 2 inces thick then lay wooden sheeting over the strips then nail the sheets to the 2x2 strips (which are anchored to the floor using tapcon anchors). No plastic is needed.
i agree with most of the answers , but if you insulate between the floor joists you dont have to go through the added expense of insulating the side walls of a crawl space as there is no heat under there anyway. you can use faced insulation but push the paper side up to the surface of your floor and not facing the ground...vapor barrier of some sort would be helpful
Yes The vapor bearier faces outside away from any subtstrates or wood.It keeps moisture from getting the insulation wet and helps stop rotting should the insulation get wet. I would use a heavy mil thickness on your plastic. I have done this projest, Not fun, but well worth it. Also there are wire hangers you can use to hold op the insulation, speeds up the process. Good Luck!
