Measured against the Florida code
The attic numbers, not a brochure
The 2023 Florida Building Code, Energy Conservation, Table R402.1.2 sets a climate zone 1 ceiling at R-30 and a climate zone 2 ceiling at R-38. Cardinal installs R-38 and checks the inches. A Florida page that lists R-49 to R-60, or R-3.2 to R-3.8 per inch for both fiberglass and cellulose, is using a different book. Table R402.4.1.1 says air-permeable insulation shall not be used as the air seal.
Quotes are prepared by Russell Y, a building scientist, BPI certified, and certified to perform blower door testing. When the door is run, the result is air changes per hour at 50 pascals, the method in R402.4.1.2. That section limits new houses in climate zones 1 and 2 to 7 ACH50. An insulation job on an existing house is not automatically that test. We report the number only when we measured it.
Insulation numbers Cardinal uses against the Florida code| Item | Number | What it means |
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| Zone 1 ceiling, Florida code | R-30 minimum | Palm Beach and Broward |
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| Zone 2 ceiling, Florida code | R-38 minimum | Not R-49 and not R-60 |
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| What Cardinal installs | R-38, depth checked | Above the zone 1 floor |
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| New blown fiberglass | About R-2.5 per inch | Not R-3.2 to R-3.8 |
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| Settled fiberglass | About R-2.2 per inch | 4 inches is about R-9 |
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| New cellulose | About R-3.6 per inch | Denser. Still not an air seal |
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| Open-cell foam | About R-3.6 per inch | A roof-deck product |
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| Closed-cell foam | About R-6.5 per inch | 2 inches is about R-13 |
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The attics on this page
Hobe Sound is mainland Martin County, ZIP 33455, just north of Tequesta. Jupiter Island is the barrier island next to it. Both can share a ZIP. They are not the same street, and the bridge matters for the appointment.
Mainland houses get the Jupiter crew, an air seal, and R-38. There is no Hobe Sound shop. The shop is 17628 Brian Way, Jupiter, FL 33478. Call (754) 253-9607 and say which side of the bridge the house is on.
Foam is uncommon on the mainland ranches. It shows up when a roof is being brought inside. A vented attic is still blown-in. 33455 is not 33469, and 33469 is not the Jupiter shop's ZIP.
The code in Hobe Sound
Hobe Sound is in Martin County. Table R301.1 lists Martin County as climate zone 2A, not 1A. Table R402.1.2 sets the zone 2 ceiling minimum at R-38. That is the code floor here, not R-30. Hobe Sound does not publish a separate number. The Jupiter shop covers the call. There is no Hobe Sound pin.
Martin County is not in the High-Velocity Hurricane Zone. Section R806.2 of the 2023 Florida Building Code, Residential, sets the net free vent area at 1/150 of the attic. The exception is 1/300 only when 40 to 50 percent of that area is within 3 feet of the ridge and the rest is in the bottom third. Insulation cannot close the soffit. R806.3 requires at least 1 inch at the eave vent.
The county zone is Table R301.1. The Boca Raton worked example, including the vent math, is the building code page. Cardinal still installs a vented attic to R-38 and checks the depth.
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