insulation
Insulation
Calculate insulation volume and rolls for walls, roofs, or floors.
Results are approximate. Verify with manufacturer specifications or consult a professional.
Project inputs
IMPERIAL
Enter a value in ft².
Enter a value in ft.
Enter a value in ft².
Includes breakage, spillage, onsite adjustments
Material output
Updates instantly as you type.
Primary output
0.64yd³
0.64 yd³
≈ 0.59 yd³ primary output
Estimated packaging
19 rolls
You need 0.64 yd³, approximately 19 rolls
Rolls
Your units
19 ea
Results are approximate. Verify with manufacturer specifications or consult a professional.
How it works
Frequently asked questions
Country defaults
United States · USD · imperial
Waste factor: 8.0%
Context & guidance
Results are approximate. Verify with manufacturer specifications or consult a professional.
About This Calculator
Calculate the exact amount of insulation material needed for walls, ceilings, floors, or roofs. Accounts for surface area, insulation thickness, material type (fiberglass, mineral wool, foam board, spray foam), waste factors (typically 5-10% for standard installations, 10-15% for complex shapes), and country-specific R-value requirements. Supports both metric and imperial units.
Step-by-Step Instructions
Measure Surface Area
For walls: measure length × height, subtract openings. For ceilings: measure length × width. For floors: measure length × width. Use the same unit system throughout. Record all measurements consistently.
Select Insulation Type
Choose material: fiberglass batts (typically 0.6m × various lengths), mineral wool (similar), foam board (various sizes), or spray foam (calculated by volume). Each type has different coverage and R-value per thickness.
Determine Required Thickness
Thickness depends on R-value requirements and material type. Typical residential: 100-150mm (4-6in) for walls, 200-300mm (8-12in) for attics. Check local building codes for minimum R-values. Thicker insulation = better energy efficiency.
Account for Waste Factor
Standard rectangular areas need 5-10% waste for cuts around obstacles. Complex shapes (irregular walls, around pipes/ducts) need 10-15% waste. The calculator applies country-specific defaults but you can adjust.
Calculate Material Needed
The calculator shows: total area, insulation volume/area needed (including waste), and number of batts/rolls/boards required. Always round up to full packages. Order 5-10% extra for future repairs.
Order Materials
Order all insulation from the same batch for consistency. Buy 5-10% extra for future repairs. Store in a dry location to prevent moisture damage. Calculate vapor barrier separately if required.
Common Mistakes
Not accounting for required R-value
Building codes specify minimum R-values for different areas (walls, ceilings, floors). Thicker insulation = higher R-value. Always verify local requirements and ensure your insulation thickness meets or exceeds minimum R-values.
Forgetting to subtract openings
Doors, windows, and other openings reduce insulation needs. Standard door: ~2.0 m², single window: 1.5-2.5 m². Always measure and subtract all openings accurately.
Underestimating waste for complex shapes
Complex shapes (around pipes, ducts, irregular walls) require 10-15% waste vs 5-10% for standard rectangular areas. Always add extra for cuts around obstacles and irregular surfaces.
Not ordering extra for future repairs
Always order 5-10% extra. Insulation gets damaged during construction or renovations, and you'll need matching material for repairs. Different batches may have slight variations.
Pro Tips
Buy all insulation from the same batch. Different batches can have slight density or thickness variations that affect R-value and fit.
For attics, account for joist spacing. Standard spacing is 400mm (16in) or 600mm (24in). Ensure batt width matches joist spacing to minimize waste.
Calculate vapor barrier separately if required. Vapor barrier area typically equals insulation area. Some insulation comes with integrated vapor barrier.
For spray foam, calculate by volume (not area). Coverage depends on thickness and expansion rate. Consult manufacturer specifications for exact coverage.
Plan your installation to minimize gaps. Gaps reduce effectiveness significantly. Cut batts carefully to fit snugly around obstacles without compressing.
Keep 5-10% extra insulation for future repairs. Store in a dry location to prevent moisture damage, which reduces R-value.
Frequently Asked Questions
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