Putting Plastic Sheeting Over Insulation

The cool surface is the sheathing assuming no exterior insulation.

Putting plastic sheeting over insulation.

Picture an ice cold can of soda on a sweltering hot day. In the vapor barrier. The humid air is indoors. Overlapping paper tabs on faced insulation and stapling is why its on there.

The plastic and the insulation will eliminate any moisture problems you have in the crawlspace such as water droplets collecting on the concrete walls. If you want to put something on the bottom of the joists to hold the insulation in place use chicken wire landscape fabric or housewrap so any water vapor from inside the house can escape. 12 ft x 400 ft clear 0 31 mil plastic sheeting. The best vapor barrier to use is roll of plastic sheeting.

Homeowners use plastic to cover their crawl spaces to control moisture and create a barrier against vapor. This article will show you how to add 6 mil plastic sheeting on the ground and insulate the walls in your crawlspace. Plastic on the outside. How to install poly over insulation.

Item 491792 model hslw12 400. Unfaced batt insulation friction fit between studs in walls with poly vapor barrier over walls and ceilings blown in attics with minimum r 40 insulation attention to detail. If you re referring to insulation in an attic you shouldn t put plastic sheeting over the top of it either for the same reason. To each is own some believe the plastic works better.

Stretch the plastic sheet tightly across the top of the wall and staple it to the studs and plates. Soon water pours off the can. Install the plastic sheeting only after the insulation wiring and plumbing have been completed. The colder the contents the more beads of sweat that form on the sides.

If water vapor diffuses or infiltrates into the wall cavity and finds the cool surface moisture problems can occur. Plastic sheeting can also help turn a crawl space into a usable storage area. After the insulation is installed it is necessary to cover it up with a vapor barrier so the glass fibers are not inhaled. More use the plastic these days without paper faced insulation.

If properly done this should not cause a condensation problem in the wall cavity unless you are leaking interior air thru gaps etc. Plastic on the outer surface of a wall in cold weather could cause problems. We use foil faced rigid insulation to keep the space under the house dry.