Cementitious foam

Cementitious foam insulation is a cement-based thermal and acoustic insulation, with an R-value which is similar to that of fiberglass It is installed as a foam with a consistency like shaving cream, or as pre-cast slabs. The current cost is similar to that of polyurethane foams.

Unlike many foam-in-place polyurethane foams, it is nonflammable and non-toxic. As it is water-based, it offgasses water vapour while curing, requiring ventilation and in some cases an dehumidifier. It cures more slowly than organic foams. However, it does not offgas volatile organic compounds as many organic foams do. Like cement, it is water-soluble until cured, but after curing it is water-resistant, but water-permeable.

It does not expand on setting, but may shrink slightly in open cavities. Structurally, it does not resemble concrete; at the low densities that make it well-insulating, it is quite fragile. It can be crumbled away to re-expose wiring or pipes, making a pile of grey powder. Also unlike concrete, it is quite lightweight.

It is not a new product, having been around for some decades, but exclusive rights to an established cementitious foam product have recently been purchased by a company that has been giving it more publicity.

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