How to estimate an attic insulation job accurately? Whether you're a homeowner getting quotes or just curious about the process, here's how pros do it in our Arkansas climate.
First, we measure the actual square footage โ not just the home's footprint. Knee walls, dormers, and complex rooflines can add 20-30% more area than you'd expect. We use a laser measure and sketch everything out, including noting ceiling heights and accessibility.
Next comes R-value requirements. In Zone 3 (our climate), IRC code calls for R-38 minimum in attics. But we usually recommend R-49 to R-60 for real energy savings. That means 16-20 inches of blown cellulose or 12-15 inches of open-cell spray foam.
Here's the math: For a 1,200 SF ranch home, expect 1,350-1,400 actual attic square feet. Blown cellulose runs $1.20-$1.80 per SF installed, so $1,620-$2,520 total. Spray foam costs $3.50-$4.50 per SF for the same job โ $4,725-$6,300.
Don't forget air sealing! We always include sealing around penetrations, which adds $300-$600 but makes a huge difference in performance. June's the perfect time to tackle this before our brutal July heat hits.
A good contractor will also check for proper ventilation, existing moisture issues, and electrical hazards before giving you a final number.
Thinking about upgrading your attic insulation? Reply or DM us for a detailed estimate โ we'll walk your attic and explain every step.