Traditional fiberglass insulation is only stapled, or placed into the wall cavities and does not seal the stud and wall cavities from end to end, or top to bottom. Air infiltration can pass through these gaps, making it far less efficient than SPF.

SPF not only adheres to, but forms to the walls and floors to create a tight seal and insulating barrier that stops this air leakage. SPF produces R-values ranging to 6.5 to 7.0 per inch.

This is significantly higher than fiberglass at 3.5 per inch. SPF is so efficient and lightweight as an insulating material; NASA even uses it to insulate the main rocket booster on the Space Shuttle.