What Is Closed Cell Foam Insulation What Is Closed Cell Foam Insulation

When insulating your home, consider using closed cell foam insulation. Learn more below about closed cell foam insulation, its advantages and disadvantages, installation costs, and safety tips. Find out which firms are the leading makers and installers of this revolutionary new insulation.

What Is Closed Cell Foam Insulation

Closed cell foam insulation is made of polyurethane, like other sprayable foam insulation. It is very dense, weighing between 3 and 4 pounds for each cubic foot of foam. The foam surface is hard enough so that you can walk on it with soft soled shoes. The bubbles inside closed cell foam are intact and tightly wedged together. They are filled with a gas that raises the insulation value of the closed cell foam dramatically compared to open cell foams and styrofoam.


You can use closed cell foam insulation below grade to insulate your basement, because it does not absorb either water and air, and prevents both from escaping through it. A small home could be insulated almost completely with closed cell foam to maximize the R-value (resistance to heat motion) of the insulation. Closed cell foam insulation can be applied year-round to your home, and can be applied over plywood and other woods, concrete, steel, galvanized steel and aluminum panels and frames. Because it remains rigid, it can actually strengthen the frame of your house, reducing its creaking noises. Closed cell foam also helps block exterior noise, keeping your home quieter inside.


Because closed cell foam is denser than open cell foam, you need to use more of it to insulate the same square footage, so it is more expensive. Its capability to act as a moisture barrier means you should not insulate the attic of your home with it. The attic will trap moisture leading to the growth of mold and mildew.

Costs per Square Foot

Closed cell foam insulation costs almost twice as much per square foot as open cell icynene foam. But closed cell foam will deliver almost twice the R-value insulating quality: its R-value is 6 per inch of depth compared to 3.6 for open cell insulation. Closed cell foam is environmentally friendly and exceeds LEED (Leadership in Energy and Environmental Design) standards because it fills in wall spaces completely, even around electrical and plumbing conduits.

Leading Makers of Closed Cell Foam Insulation

Foam-Tech (TM) of Vermont is a leading maker and installer of closed cell foam insulation. LaPolla's foam wall insulation is called Foam-Lok (TM). Icynene (TM) produces both closed cell and open cell foam insulation, as does NCFI. Their closed cell foam is called InsulStar (TM).

Safety Tips

Hire a licensed and trained polyurethane foam installer to insulate your home with closed cell foam. Allow your home to air out for a few hours after a closed cell foam installation to vent out the microscopic polyurethane particles in the air. It is recommended that you apply closed cell foam insulation while your home is being built or during extensive renovations that expose wall studs and roof joists. Unfinished basements and garages can easily be insulated with closed cell foam after construction.

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