Is EPS good for basement walls?

Two-inch extruded polystyrene foam (XPS) is typically used as one-inch foam is too fragile to place under a slab. Expanded foam (EPS) is a less expensive option, and considered better for the environment, but you would need to use high-density Type II EPS for this application.

Is foam board good for basement walls?

Extruded polystyrene foam board (XPS) XPS foam boards are naturally semi-permeable, which makes them a common insulation material for basement walls. It uses recyclable materials in manufacturing and is available in faced and unfaced versions. Its special properties make it a vapor retarder but not a vapor barrier.

How thick should foam insulation be in a basement?

The thickness of foam insulation in basement walls will range between two to seven inches, depending on where you live and whether you use open or closed-cell spray foam insulation.

Does EPS need a vapor barrier?

A: No, although EPS has a low water vapor transmission rate, EPS is not a vapor barrier. Rather it “breathes”, and therefore does not require costly venting as do other insulation materials, which would otherwise trap moisture within walls and roof assemblies.

What is the cheapest way to insulate basement walls?

The smart and inexpensive way to insulate joist bays is to use extruded polystyrene (XPS) foam insulation panels cut to size to fit inside the bay and “glued” in with expanding foam. When the expanding foam hardens, trim away the excess and cover the foam with a piece 1/2″ thick drywall to meet fire code.

Does EPS absorb water?

A: EPS is non-hygroscopic and does not readily absorb moisture from the atmosphere. Its closed-cell structure reduces the absorption and/or migration of moisture into the insulation material.

Is EPS water proof?

EPS is resistant to water and moisture. This means that it does not absorb them and that its insulating performance is not compromised when in contact with these elements. Insulation boards made of expanded polystyrene can make a home healthier because they will not contribute to mildew formation.

What kind of insulation is best for basement walls?

Rigid foam sheets are best for DIYers who are insulating basements prior to framing the walls. Rigid foam also works well when the concrete or block walls are smooth and flat. Rigid foam insulation is easy to use. In addition to scoring, it can be cut by an ordinary wood saw.