Roofing Calculators
Mansard Roof Area Calculator
Calculate the total area of a mansard (French-style) roof with steep lower slopes and a shallow upper slope. Get upper and lower slope breakdowns, roofing squares, and waste-adjusted totals.
Enter Dimensions
Results update automatically as you change inputs.
Mansard Roof Cross-Section
Lower Slope Area
0.00 m²
0.00 ft²
Upper Slope Area
0.00 m²
0.00 ft²
Total Roof Area
0.00 m²
0.00 ft²
Area with Waste (20%)
0.00 m²
0.00 ft²
Roofing Squares
0.00
1 square = 100 ft² (9.29 m²)
Lower Slope Multiplier
0.0000
Upper Slope Multiplier
0.0000
Slopes
70° / 20°
Calculation Breakdown
Gambrel Roof Calculator
Calculate gambrel (barn-style) roof area with dual-slope geometry. Similar to mansard but with only two sides.
Calculate Gambrel Roof →Hip Roof Calculator
Calculate hip roof area with slopes on all four sides. Compare with your mansard roof results.
Calculate Hip Roof →All Roofing Calculators
Browse our full suite of free roofing calculators for every roof type and measurement need.
View All Calculators →Frequently Asked Questions
Common questions about mansard roofs and calculating their area
What is a mansard roof?
A mansard roof is a French-style four-sided roof with two slopes on each side — a steep lower slope and a shallow upper slope. This design maximizes usable attic space and is common on heritage buildings.
What angles are typical for mansard roofs?
Lower slopes are typically 60–80°, while upper slopes are usually 15–25°. The steep lower slope is what creates the usable attic space beneath the roof.
Why do mansard roofs need more waste allowance?
Mansard roofs have complex geometry with many angle changes, hip-like corners, and the transition between upper and lower slopes. This creates significant material waste, typically 20–25%.
Are mansard roofs common in Australia?
Mansard roofs are found on heritage buildings, particularly in areas with French-influenced architecture. They are uncommon on modern homes but are sometimes used for renovations to maximize attic space.
Can I convert my roof to a mansard style?
Yes, but it is a significant structural modification requiring engineering approval and council permits. The benefit is creating a full additional storey within the roof space.
Planning a Mansard Roof Project?
Mansard roofs require specialist design and construction. Our heritage restoration team has experience with this complex roof style.