Spray foam is a type of insulation material made from a mixture of chemicals that expand when sprayed. It creates a solid layer that fills gaps and cracks, providing excellent thermal resistance. This helps to keep homes and buildings warm in winter and cool in summer, improving energy efficiency. There are two main types of spray foam: open-cell and closed-cell. Open-cell foam is softer and more flexible, while closed-cell foam is denser and provides a higher R-value, which measures insulation effectiveness. Both types are commonly used in construction and renovation projects to enhance insulation and air sealing.