A Mansard roof is a boxy style of roof that was named for the French Classical architect François Mansart, who lived from 1598 until 1666. The top of a Mansard roof is flat and broad with multiple slopes extending from it. This style of roof often has dormer windows extending from it. If you want to calculate the area of a Mansard roof, you must use the roof's measurements in various geometrical area formulas.

Record the measurements for the dimensions of the roof and display the measurements on a sketch of the roof.

Look for geometrical shapes within the diagram. Mansard roofs can be divided into rectangular, triangular and trapezoidal shapes.

Find the area of each shape. For triangles, multiply the base times the height and divide by two. For rectangles, multiply the width times the height. For trapezoids, first add the lengths of the parallel sides and multiply this sum by the height. Finally, divide your answer by two.

Add the individual areas of each shape to find the total area of the roof.