- Project plans
- Project activities
- Legislation and standards
- Industry context
Last edited 20 Oct 2020
A mansard roof, also known as a French or curb roof, is a roof characterised by that fact that each of its four sides has two pitches, the lower pitches being steeper than the upper pitches. It is similar to a gambrel roof but differs in that it displays the same profile on all sides (whereas a gambrel roof has vertical gables at either end). The lower slope is commonly fitted with dormer windows.
Mansard roofs allow for increased space beneath their steeper sides. They maximise headroom inside the upper storey of the building whilst lowering, what would if it were simply-pitched, be a very tall roof. The mansard form can also help water runoff, as the pitch increases towards the eaves, where the runoff is likely to be at its greatest.
The commonly-attributed earliest example of a mansard roof is the Louvre, designed by Pierre Lescot around 1550. It was popularised in the French Baroque period by Francois Mansart and became widely used during the Second French Empire (1852-1870) as well as in the United States and Europe. One of the factors attributable for its popularity in France was that houses were taxed by height or the number of storeys below the roof. The design of the mansard enabled the creation of an additional floor without having to pay additional tax.
 Related articles on Designing Buildings Wiki
Featured articles and news
Prioritising tax considerations.
The four D creative process: discover, define, develop and deliver.
National Cyber Security Centre initiative is announced.
Reviewing trends and projections.
Legislation will establish initiatives to move towards net zero.
How to document contractor employment status.
Tech tools to help manage people and space post-pandemic.
A style that ranges from mock Tudor to arts and crafts to the 'Wrenaissance'.
Free guide from Secured by Design.
BREEAM strategy for sustainability and the circular economy.
Free tool to improve the construction programming process.
Are buildings doing what they're supposed to be doing?
Cities with quick access to everything by foot or bike.
The pressures and pinch points of global destinations.