Spray Foam Insulation: Closed-Cell


Closed Cell foam makes a very dense and hard finish that has more mass than open cell foam. Yet it makes an ideal barrier against both moisture and air.


Ideal areas to apply Closed-Cell

  • Crawl areas
  • Retrofit for Exterior walls
  • Exteriors of foundations
  • Exterior areas that contact water
  • Basement walls
  • Roof areas

Every single kind of expansive spray foam has within it tiny cells or bubbles. When the closed cell is applied, most of the cell structures stay intact, even after the foam expands. The end result is  hard, uncompromising material that seals  in air, and also protects against moisture.

These foam have a lot of density. The range is from 1.7 lb. per cubic foot to 2 lb. per cubic foot. This however means that the foam is stronger. In fact the foam makes the structure stronger. This means that it can help protect homes extreme winds during storms, and for roofs this means it can support more weight.


The R-value for Closed-cell foam is impressive. The range is between 6 to 7 per inch, this is double than some forms of insulation and over 40 percent better than open-cell foam. This makes it the right choice for limited areas of insulation like standards walls and roofs. Moreover, it is the right choice in places that come into contact with water.

Application Process

The availability of Closed-Cell spray foam comes in  many different shapes and sizes. First, for small  jobs, small cans like those available at Home Improvement Retailers can work to fill small areas and gaps. For example can lights, and around can lights covering recessed lighting. A second kind would be kits. Kits come with recyclable canisters, a hose, a gun and come with 200 and 600 board feet quantities. These work for places like rim joists and ducts. The first to applications are one-part formulations and involve no mixture. The larger jobs, use a two part mixture. In these cases a truck is necessary to mix the foam and apply it with a hose.





  • Makes the frame stronger
  • R-value per inch higher
  • Seals off areas for air barrier
  • Protects against moisture
  • Sound Barrier
  • Can be used as material for roofs



  • Density makes it heavier
  • Covers less area-more material needed

Water can be trapped if not applied properly



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