Quick Answer: How Thick Should Foam Board Insulation Be?

Can you leave foam board insulation exposed?

As far as I know, most types of rigid foam insulation can’t be left exposed, but need to be covered with a layer of drywall for fire resistance..

Can you use rigid foam insulation between studs?

Even with its flaws—namely, its inability to perfectly mold to the bays between the studs—rigid foam insulation will be a better bet than no insulation. Using low-expanding spray foam sealant to seal those gaps further increases rigid foam’s insulating properties between studs.

Does foam board insulation need to be covered?

Rigid foam insulation, whether it is expanded or extruded polystyrene, does have to be covered if it is installed in the interior of a building. … Because this type of insulation is made from plastic, it is combustible and may give off highly toxic fumes when burning.

Which side of foam board insulation faces out?

If you’re wondering whether to put the foil side of foam insulation board shiny side in or out, consider whether you want to make the space inside warmer or cooler. If you want to make the space warmer, the foil should face inside so it can reflect radiant heat back into the room.

Does foam board insulation mold?

Foam building insulation, in both spray foam and foam board products, is resistant to mold growth but as we will explain here it is not absolutely mold-roof, and on occasion we do find mold growth on the surface of even closed-cell foam, in open-celled foam (rare), and on th surface of EPS and other foam insulating …

How thick should insulation board be?

What thickness of board is available? Rigid boards are sold with different thicknesses. They start at 20mm and go up in 10-15mm increments up to 200mm.

What is the R value of 2 inch foam board?

Expanded Polystyrene. Also called Styrofoam insulation, this is the least expensive material. It provides R-values that range from 3.6 to 4.2 per inch.

Do you need a vapor barrier with rigid foam insulation?

Rigid foam insulation is it’s own vapour barrier in this application, so you don’t need to use the poly. Just make sure you tuck tape all the joints. … Yes, you can go right over your existing blown in insulation with batt insulation, just make sure you butt the batts up tight against one another so there are no gaps.

What is the difference between pink and blue foam board?

Main Difference Between Pink And Blue Foam Boards The two products also have the same insulating power. However, blue foam boards are manufactured by Dow Chemical Co. whereas the pink foam boards are manufactured by Owens Corning company. The boards are marketed under different brand names.

What is the best foam board insulation?

Choose the right type of rigid foam for your needsPolyisocyanurate: Known as polyiso for short, polyisocyanurate foam has the highest R-value per inch (R-6.5 to R-6.8) of any rigid insulation. … Extruded polystyrene: Extruded polystyrene (XPS) rigid foam is usually blue or pink in color, with a smooth plastic surface.More items…

Can you walk on foam board insulation?

The rigid foam isn’t the issue. It’s the drywall/plaster/sheathing supporting the foam. These products won’t support the weight because they are suspended from the joists and may not be strong enough anyway. You can walk on rigid foam, lots of guys use it as knee boards for doing concrete work.

Do you need an air gap for insulation?

Solid walls however must be faced with an insulation product, so they can often eat into floor space depending on the thickness of the insulation as an air gap is needed to prevent condensation and moisture build up. Insulation with a moisture barrier means you don’t need to leave an air gap during installation.