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
Fort Lauderdale splits at the water and again at I-95. Victoria Park and Coral Ridge in 33304, Las Olas and Rio Vista in 33305, and Idlewyld are older houses, low attics, closet hatches, and plaster ceilings. Harbor Beach in 33316 is tighter still, often a small scuttle on a deep-water lot.
Southwest 33312, including Riverland, is the wider attic. Lauderdale Isles is canal houses, mostly one story, not a high-rise. A condo tower on the beach has no attic. There is no Fort Lauderdale shop. The closer Cardinal address in Broward is 681 SW 16th Ter, Pompano Beach. The Boca shop is 4263 NW 1st Ave.
An old Fort Lauderdale attic is often a crawl. The job is still a seal and a blow to R-38 when the fill is dry and the lid is sound. Foam shows up on additions and on flat-roof sections that were never vented. It does not replace blown-in on a vented hip roof.
The code in Fort Lauderdale
Fort Lauderdale is in Broward County. Table R301.1 lists Broward as climate zone 1A. The zone 1 ceiling minimum is R-30. Fort Lauderdale does not publish a separate insulation number.
Broward County is in the High-Velocity Hurricane Zone, with Miami-Dade. The whole county is in it, not just the beach. Chapter 44 of the 2023 Florida Building Code, Residential, sends roof assemblies, wall coverings, and windows to the stricter Building-code chapters. Roofing and openings used there need approval for HVHZ use, a Miami-Dade or Broward Notice of Acceptance or a Florida Product Approval that includes the HVHZ. That is a roof and window rule. It does not change the attic ceiling from R-30, and a blown-in job does not carry a roof product approval. 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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