Roof Deck vs Attic Floor
Spraying the underside of the roof deck creates a conditioned attic — best for homes with HVAC or ductwork in the attic. Spraying the attic floor keeps the attic vented and is cheaper for homes with no equipment up there.
Open Cell at the Deck
Open cell at 5-7 inches gives you R-19 to R-26 with full air sealing. It's the most cost-effective conditioned-attic system.
When Closed Cell Wins
Low-slope roofs, hurricane-prone areas (rare here), and homes where you want maximum R-value in minimum thickness.