Florida New Home Attic Insulation Rules

Mandatory R Values

• The Florida Residential Code determines the minimum R-values for insulation used in new homes. An R-value refers to insulation's ability to resist the conduction of heat. A higher R-value corresponds to a more effective insulator, and it can vary depending on insulation's material, thickness, density and installation. All homes must have insulation with an R-value of 6 or higher on roofs, building exteriors and in attics with ceiling insulation. Vented crawl spaces may have an R-value of 4.2. You can determine an R-value by multiplying the insulation material's thickness (in inches) by its square footage, then multiplying the answer by the length of time (in hours). Then, divide your new answer by the heat energy lost (in British thermal units).

Blown-In Insulation Rules

• You cannot use blown-in insulation, also known as loose-fill insulation, in attics measuring less than 30 inches from the top chord of the lower trusses to the bottom chord of the upper trusses at the roof's ridge. A "chord" refers to the individual beams at the top and bottom of a truss structure. Likewise, you cannot apply blown-in insulation to attics with a height of 10 feet or greater, measured from any point located 30 inches from the ceiling surface to the roof's eaves. Building Code also prohibits blown-in insulation for any ceiling with a pitch exceeding 5 over 12. Whether batt insulation or blown-in insulation is used, the insulation must not interfere with the natural ventilation to the roof eave area. In cases of blown-in insulation, this may necessitate insulation dams and chutes. Vented attics require an aperture of one square foot per 300 square feet of ceiling area.

Insulation Certification Card

• In order to regulate the effectiveness of insulation materials, the Florida Building Code requires that all insulation materials that do not have a "readily apparent" R-value must feature an official insulation certification card, signed by the insulation contractor. This certification requirement applies to insulation used to line ceilings from attics as well as insulation in walls and floors. The card must indicate the insulation manufacturer, insulation type, insulation's R-value and thickness, the insulation's location within the home and an indication that the insulation does not block the attic's requisite ventilation. Finally, it must include the contractor's name, address and signature and the date of installation.