Attic Insulation in Climate Zone 2A (Tampa Bay)

Tampa Bay is IECC Climate Zone 2A — hot-humid. DOE guidance for attics here is roughly R-30 to R-60. We treat R-38 as the practical target on existing homes.

Most 1990s–2000s production homes in Wiregrass, New Tampa, and Brandon have 6–8 inches of whatever the builder blew in. That’s not R-38. It’s why the upstairs is five degrees hotter than the thermostat.

Insulation without ventilation just holds heat against the roof deck. We look at both. Soffit intake, baffles so blow-in does not choke the eaves, and ridge exhaust (often GAF Cobra®) is the simple version that works. Florida code wants 1/150 net-free area, or 1/300 when at least 40–50% of the venting is high.

GAF’s Golden Pledge® does not cover damage from inadequate ventilation. That is not a footnote. If the attic cannot breathe, the warranty will not save a cooked deck.

Fiberglass blown-in is usually our preference in this humidity. Cellulose packs tighter but can hold moisture. Neither one fixes a roof that’s due. If we’re tearing off anyway, that’s the day to top off the attic.

Section 25C tax credits may apply. We give you the product and labor documentation. Your tax person decides the rest.