Closed-Cell Spray Foam

Closed-cell foams are characterized by their rigidity and strength in addition to the high R-value. The closed-cell nature provides a highly effective air barrier, low moisture vapour permeability (the “Perm” rating) and excellent resistance to water.

It is applied as a liquid, expanding 40 times its volume in seconds. Because it is a higher-density foam it feels much stiffer than lower-density foams — and studies show wall racking strength can be doubled or tripled when closed-cell foam is applied.

Benefits

• R-value double that of other insulation materials
• A moisture barrier at 50mm thickness or more
• Dramatic savings in heating & cooling costs
• Suitable for exterior and below-grade applications
• Creates a seamless air barrier
• Prevents the growth of mould
• Highest cost/output ratio of all foam types

Where Closed-Cell Is the Right Choice

Closed-cell foam is the denser of the two products, roughly two pounds per cubic foot, with sealed cells that do not connect to each other. That structure gives it the highest R-value per inch of any commonly used insulation, makes it resistant to moisture and lets it add genuine rigidity to the assembly it is bonded to.

• Basement and crawl space walls, where moisture matters
• Rim joists and band joists
• Metal buildings, pole barns and agricultural structures
• Cathedral ceilings and any assembly with limited depth
• Cold storage, freezers and refrigerated rooms
• Exterior walls in retrofits where the cavity is shallow

Vapour Control Without a Separate Layer

At sufficient thickness, closed-cell foam acts as its own vapour retarder, which removes the need for a separate poly sheet and the detailing errors that come with it. This is the main reason it is specified below grade in our climate: it keeps the dew point inside the foam rather than on the cold concrete behind it.

Worth the Extra Cost?

Closed-cell costs more per square foot than open-cell because there is more material in it. Whether that is worth it depends entirely on the assembly. Below grade, in tight cavities and in metal buildings, it is the correct product and the extra cost buys performance you cannot get another way. In an interior partition, it is money spent on properties you do not need.