Concrete Floor Vapor Barrier Insulation

The best option under a concrete slab is foamular 250 which delivers r 5 per inch of thickness along with 25 psi of compressive strength.

Concrete floor vapor barrier insulation. After the insulation is in place you will want to add a vapor retarder sometimes called a vapor barrier if you need one. A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter. Because extruded polystyrene insulating board will absorb little moisture the vapor barrier can be placed above or below the slab insulation. Very hot and humid climates may benefit from an exterior vapor barrier that keeps outside humidity from penetrating into walls.

If you have a framed wall that is adjacent to a concrete foundation wall where the vapor barrier is next to the drywall in front of the studs the fiberglass insulation gets wet and becomes a breeding ground for mold. The american concrete institute s guide for concrete floor and slab construction recommends that the thickness of the vapor retarder be at least 10 mils. This barrier is meant to keep moisture from getting to the insulation in the walls and ceilings and it is required by building codes when insulating most houses. Lay vapor barrier.

In any case the vapor barrier must point to the warm side. So this is clearly an ineffective solution. Vapor barriers are sheets of plastic or other material placed on one side of insulation sheets. Overlap the seams about 6 to 8 inches and seal the seams with waterproof construction tape.

The barrier under concrete thermal insulation and vapor retarder product family is a high performance simple to use and labor saving product for all of your under slab under concrete and radiant floor insulation projects. For a vapor barrier below a concrete floor slab most choose 6 to 10 mil polyethylene. Insulating concrete garage floors begins with covering the entire floor with 6 mil polyethylene which will serve as a vapor barrier. A vapor barrier against the concrete surface is generally recommended before wood framing or flooring materials are installed.

When the mold grows it will spread to everything around it studs drywall etc. If you have a concrete floor that s in continuous contact with a source of moisture you re going to have problems. The barrier s unique core material is an expanded polystyrene eps with a jobsite tough heavy duty poly film. Reflectix and similar reflective radiant barrier products provide almost no insulation under or on top of a concrete slag just r 1 for reflectix.

Below grade walls and floor slabs transmit ground moisture through concrete walls or slabs. Puncture studies of 6 8 10 and 20 mil vapor retarder materials have shown that 10 mils is the minimum thickness that should be considered and thicker material may be necessary over. Not every wall does.