Context
User is building a 24’ by 40’ pole barn-style garage with 10’ walls and a 10/12 pitch A-frame loft that will be used as an apartment. They plan to frame the lower level with 2x4s on 16” centers to finish with drywall. Walls use 4x8 posts spaced 5’ apart.
Key Points
- Lower level walls: Recommend mineral wool or fiberglass batts in 2x4 framing; optionally pair with rigid foam for higher R-value (~R-35+).
- Roof/ceiling: Use closed-cell spray foam (R-6.5/inch) to achieve R-35 to R-49; unvented cathedral ceiling suggested for apartment.
- Wall cavities between pole barn posts: Fill 4x8 cavities (~7.25”) with foam board + batts, or full spray foam for R-45+.
- Floor of loft: Use R-30+ batts or rockwool for sound and thermal isolation.
- DIY spray foam: Apply 4-6” thickness depending on zone; estimated ~4,320 board feet for lower garage walls at 4”.
- Froth-Pak 650 example: 7 kits for 4” coverage across 1,080 ft² area (garage walls minus doors).
- Safety and performance tips for spray foam: PPE, layer control, temp regulation, sealing joints.
Actions
- Create visual diagram of wall and roof insulation layers — stage:: 3
- Provide material cost estimation for hybrid vs spray foam approach — stage:: 3