A 54 m² horizontal plan becomes about 62.35 m² of sloped roof area at a uniform 30° pitch.
Assumptions
We model a simple symmetrical gable roof with two equal 30° pitches above a 9 × 6 m rectangle, without additional eaves. This is a geometry exercise, not a structural design.
Horizontal projection
9 × 6 = 54 m² viewed from above.
Pitch correction
cos(30°) ≈ 0.866025. Combined sloped surface: 54 ÷ 0.866025 ≈ 62.35 m².
Material allowance
With a hypothetical 12% allowance, the equivalent material area is 62.35 × 1.12 ≈ 69.83 m². Real tile, sheet or membrane quantities depend on overlaps, useful unit coverage and manufacturer instructions.
Skylight example
A 0.80 × 1.20 m skylight can be drawn on the roof plan for orientation. Do not automatically subtract that rectangle from a purchase: flashing, cuts and junctions may require additional material.
Result: roughly 62.35 m² of roof surface before allowance. No structural, drainage or installation safety checks are included. TechoExacto is for preliminary estimates.
Try it in TechoExacto
Enter your own measurements and compare the result. Actual quantities depend on your materials.