Insulation Board Calculator
Calculate boards needed for floors, walls, and lofts.
NAIBC / IRC codes
References & Sources
Standards Cited
- IECC — International Energy Conservation Code
Sets minimum insulation R-value requirements by climate zone that determine insulation thickness choices - ASTM C578 — ASTM C578: Standard Specification for Rigid, Cellular Polystyrene Thermal Insulation
Defines standard rigid foam insulation board specifications and thermal performance
Formulas Used
- Board area:
boardAreaM2 = (boardWidth / 1000) x (boardLength / 1000)
Source: Basic geometry — Common sizes: 600x1200mm (0.72 m2), 1200x2400mm (2.88 m2) - Boards required:
boardsRequired = ceil(area / boardAreaM2)
Source: Standard quantity calculation - Boards with wastage:
boardsWithWastage = ceil(boardsRequired x (1 + wastage/100))
Source: Industry standard practice
Key Assumptions
- Standard board sizes vary by manufacturer (e.g., Owens Corning, Dow, Rockwool); common sizes include 2x8 ft and 4x8 ft — ASTM C578 / manufacturer catalogues
- Common thickness range: 1"-2" for walls, 2"-6" for attics depending on climate zone — IECC
- Typical wastage allowance of 5-10% for cutting and fitting — Industry standard practice