Insulation R-value requirements are based on Climate Zone the project is located:
* A minimum of R-20, spray applied insulation is acceptable
Insulating homes to EarthCraft standards will ensure that each home features a well performing thermal envelope.
See above language for minimum cavity and continuous insulation values
- The above chart references the 2015 IECC with Georgia Amendments. Where local code is more stringent defer to the higher required R-value.
- Attic knee walls require minimum R-18 plus sealed attic-side air barrier (e.g., R-13 +R-5 rigid insulation, R-15 + R-3 rigid insulation, R-19 batt in 2x6 cavity with air barrier material).
- Roofline insulation may not be used in a vented attic.
- Framed floors over basement/crawlspace only require insulation if basement/crawlspace is outside of building envelope.
- If insulating a steel joist floor, R-6 continuous insulation must be installed in addition to floor insulation listed above.
- If insulating a steel studded wall or steel header, R-5 continuous insulation must be installed in addition to wall insulation listed above.
- Garage walls are considered exterior walls.
- Foundation walls require insulation if inside building thermal envelope.
- Flat ceiling insulation not installed to full depth (e.g., under attic platforms, over wall top plates at eaves, etc.) must be modeled at actual installed R-value but may not be modeled or installed less than R-21, and no more than 500 sq. ft. or 20% of the total insulated ceiling area, whichever is less, may be less than R-38 in Climate Zones 2 and 3 and R-49 in Climate Zone 4.
- Slabs greater than 12” below grade as measured from the top of the slab are not required to have insulation.
- Permanently install insulation to crawlspace walls and extend downward from the termite inspection strip to within 9” of the finished interior grade adjacent to the foundation wall.
- Provide a 3” inspection strip immediately below the floor joists to allow inspection for termites. (The inspection strip may be insulated with a removable section of insulation but is not required to be insulated.)
- Paper-faced batts may not be used (see DU 10)
The EarthCraft Technical Advisor will visually confirm compliance of criteria during midconstruction and final inspections.