Which two types of spray foam insulation are commonly used?

The correct answer is based on the common use of two specific types of spray foam insulation, which are polyisocyanurate and polyurethane. Both of these materials are widely recognized and utilized for their excellent thermal resistance and versatility in various applications.

Polyisocyanurate foam insulation is appreciated for its high R-value per inch, offering superior thermal performance, which is particularly important in energy efficiency. It often features a reflective foil facing, enhancing its ability to reduce heat transfer.

Polyurethane foam insulation, on the other hand, is known for providing exceptional airtightness when applied, which helps in reducing air leaks and improving energy efficiency. It is widely used in residential and commercial settings for both wall and roof insulation as well as in various industrial applications.

The other options provided include materials that may serve insulation functions but are not categorized as spray foam. EPS (Expanded Polystyrene) and XPS (Extruded Polystyrene) are rigid foam board insulations used in various applications but do not fall under the spray foam category. Fiberboard and cellulose are more traditional insulation materials, while mineral wool and fiberglass are also used for insulation but do not fit the spray foam classification. Therefore, the focus on polyisocyanurate and polyurethane as spray foams is