Originally Posted by
Jeff Eastman
"What code section? Why, the same one which requires a minimum of R-19 insulation on the ceiling to an unconditioned attic above".
1) Is this code in the IRC? Can you state it for me? I really could you the code, something came up today and I'd love to have it.
From the IRC.
- SECTION N1102
- - BUILDING THERMAL ENVELOPE
- - - N1102.1 Insulation and fenestration criteria.
The building thermal envelope shall meet the requirements of Table N1102.1 based on the climate zone specified in Table N1101.2.
According to the IRC, the minimum attic ceiling insulation in Florida would be R-30, however, the Florida Building Code only requires a minimum attic ceiling insulation of R-19, which is why I keep saying R-19. You would need to think in terms or R-30 or greater, depending on the R value required by the table for your Climate Zone (see Figure N1101.2 or Table N1101.2, which lists states and counties and gives the Climate Zone for them.
Also, You are refering to , for example , if an attic pulldown door is in a garage under an attic, the door cover needs to be at least insulated with R19?
The garages I see are (for the vast majority of them) uninsulated and unconditioned, thus no insulation would be required for an attic access hatch cover, stair or no stair attached.
1) How thick is R19? 4 inches?
I don't recall, but the IRC says that R-19 is allowed to be compressed into a 2x6 stud cavity (see sub note 'a' for Table N1102.1). Florida allows no compression, or derating of the R value begins to take affect.