The best vapor barrier to use is roll of plastic sheeting.
Plastic over insulation in garage.
Featuring fiberglass or polystyrene panels these kits will generally come with enough pre cut panels to cover a garage door with a width of 9 ft.
Plastic on the outside.
Danny lipford in an uninsulated attic over a garage.
Must be measured and cut to fit walls or flat surfaces.
If your garage is 45 degrees and you have a bonus room heated to 72 degrees above the garage the vapor retarder faces the upstairs room.
Plastic on the outer surface of a wall in cold weather could cause problems.
Six mil polyethylene plastic comes in rolls of various dimensions.
Purchase plastic in dimensions that limit the number of seams between plastic sheets.
Attics walls and between crawlspace joists.
If you are insulating the garage ceiling not only by the truss level but also up by the roofline then you must leave at least 1 1 2 to two inches of air between the fiberglass and the underside.
Stops heat loss into your attic.
Make sure you have enough ventilation on your roof as well.
There should be a continuous ridge and soffit ventilation.
Equipped with pretty much everything you need you can buy a garage insulation kit at a variety of retailers including home depot lowes or amazon.
The humid air is indoors.
Most insulation is made of fiberglass and fits into the walls between the studs before drywall is installed.
The cool surface is the sheathing assuming no exterior insulation.
Insulating the area in the attic over a garage might keep the temperature a little more stable in the garage but it does little to reduce the amount of energy needed to heat and cool your house so it s not a good investment of your energy dollars.
Install the plastic sheeting only after the.
Your bonus room subfloor usually osb or plywood is a perfectly adequate vapor retarder so no polyethylene is needed even in the 1970s scenario before building science made us smarter.
Glass fibers in puffy strips with or without a paper or aluminum face.
Wall insulation keeps out cold.
After the insulation is installed it is necessary to cover it up with a vapor barrier so the glass fibers are not inhaled.
Stops heat loss into your attic.
Best for long unobstructed spaces like over attic joists.