Spray Foam Insulation: Open Cell vs. Closed Cell. What’s the difference? 7


One of the most com­mon ques­tions we get is “What’s the dif­fer­ence between open cell and closed cell spray foam insu­la­tion?”
The dif­fer­ence is in the struc­ture of the cells.

THE STRUCTURE OF THE CELLS
Both closed cell and open cell spray foams con­sist of tiny, micro­scopic cells grouped together to cre­ate insu­la­tion. The cells in open cell spray foam remain open. With closed cell spray foam, the cells are closed.

OPEN CELL AND CLOSED CELL SIMILARITIES
Open cell and closed cell spray foams share some great fea­tures. Most impor­tantly, they both pro­vide a high R-value. They both also air-seal the build­ing enve­lope by elim­i­nat­ing gaps and voids that batts may miss. Open cell and closed cell spray foams are installed in a sim­i­lar man­ner, using the same equip­ment. The two prod­ucts, how­ever, have a few differences.

OPEN CELL SPRAY FOAM INSULATION
The open cell struc­ture of open cell spray foam cre­ates an insu­la­tion that is soft, much like the con­sis­tency of a marsh­mal­low. The open cell struc­ture makes this insu­la­tion a good choice for south­ern cli­mates. The open cells also allow mois­ture to per­me­ate the insu­la­tion. It is not rec­om­mended that this insu­la­tion be used below grade, or in any instance that it may come into con­tact with mois­ture. A vapor bar­rier is required.

CLOSED CELL SPRAY FOAM INSULATION
The closed cell struc­ture of closed cell spray foam cre­ates an insu­la­tion that is strong and rigid, adding strength to the build­ing struc­ture. Closed cell spray foam’s most impor­tant fea­ture is that this insu­la­tion is a vapor bar­rier: mois­ture can­not travel through the closed cells. An addi­tional vapor bar­rier, usu­ally a layer of plas­tic is not nec­es­sary when insu­lat­ing with closed cell spray foam.

PRICE COMPARISON
Spray foam insu­la­tion is most com­monly priced by the board foot. A rep­re­sen­ta­tive will read your plans or come to your project and mea­sure how many board feet of spray foam you will require.

When com­par­ing the price of open cell vs. closed cell spray foam, be sure to keep in mind that you will have an addi­tional cost of a installing a vapor bar­rier with open cell spray foam. Many times the prices are sim­i­lar once the vapor bar­rier is fig­ured in.

by Jenny Bulfer

The top is a sample of open cell spray foam insulation. The bottom is closed cell spray foam insulation

TOP: Open Cell Spray Foam Insu­la­tion
BOTTOM: Closed Cell Spray Foam Insulation


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7 thoughts on “Spray Foam Insulation: Open Cell vs. Closed Cell. What’s the difference?

  • neal bowman

    We were won­der­ing approx­i­mately how much it would cost to do a steel build­ing. Its our garage that mea­sures 24 x 36 with 10 foot side walls. We would want to have time to save up for some­thing like this. It is all metal studs. thanks

    • Jen Bulfer Post author

      Neal, Just call the office toll free at 855–612-8038. Esti­mates are free. Then you’ll have an esti­mate when you are ready.

    • Jen Bulfer Post author

      In north­ern cli­mates, def­i­nitely closed cell…but be care­ful how it is installed. Don’t let your installer spray it directly to the bot­tom side of the roof to cre­ate a “hot deck”. In metal roofs, this can make them noisy. Keep some air flow between the insu­la­tion and the roof deck. How­ever, in some instances there isn’t enough room in the truss. An on-site visit by your installer is ideal. They can walk you through your options.

  • EcoInsulation

    It should also be men­tioned that this type of insu­la­tion, when installed prop­erly, never needs replac­ing. That can­not be said of fiber­glass or batt insu­la­tion when, once they get wet, lose their insu­lat­ing abil­ity and need to be replaced.