Mansard roof
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.
When viewed from near the building at ground level, the upper slope is often not visible.
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.
NB The National Planning Policy Framework (NPPF), published by the Ministry of Housing, Communities and Local Government in December 2024, defines a mansard roof as: ‘A type of roof that is characterised by two slopes, the lower steep and the upper shallow. It is generally regarded as a suitable type of roof extension for buildings which are part of a terrace of at least three buildings and at least two stories tall, with a parapet running the entire length of the front façade (reference: Create Streets, 2021, Living Tradition).’
[edit] Related articles on Designing Buildings
Featured articles and news
Combating burnout.
The 5 elements of seiri, seiton, seiso, seiketsu and shitsuke.
Shading for housing, a design guide
A look back at embedding a new culture of shading.
The Architectural Technology Awards
The AT Awards 2025 are open for entries!
ECA Blueprint for Electrification
The 'mosaic of interconnected challenges' and how to deliver the UK’s Transition to Clean Power.
Grenfell Tower Principal Contractor Award notice
Tower repair and maintenance contractor announced as demolition contractor.
Passivhaus social homes benefit from heat pump service
Sixteen new homes designed and built to achieve Passivhaus constructed in Dumfries & Galloway.
CABE Publishes Results of 2025 Building Control Survey
Concern over lack of understanding of how roles have changed since the introduction of the BSA 2022.
British Architectural Sculpture 1851-1951
A rich heritage of decorative and figurative sculpture. Book review.
A programme to tackle the lack of diversity.
Independent Building Control review panel
Five members of the newly established, Grenfell Tower Inquiry recommended, panel appointed.
Welsh Recharging Electrical Skills Charter progresses
ECA progressing on the ‘asks’ of the Recharging Electrical Skills Charter at the Senedd in Wales.
A brief history from 1890s to 2020s.
CIOB and CORBON combine forces
To elevate professional standards in Nigeria’s construction industry.
Amendment to the GB Energy Bill welcomed by ECA
Move prevents nationally-owned energy company from investing in solar panels produced by modern slavery.
Gregor Harvie argues that AI is state-sanctioned theft of IP.
Experimental AI housing target help for councils
Experimental AI could help councils meet housing targets by digitising records.
Comments
I love this design!!! I have a home with a mansard roof and I am trying to renovate the front. I am wondering if you know the dimensions of the two windows on each side of the door?