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
Shortage of high-quality data threatening the AI boom
And other fundamental issues highlighted by the Open Data Institute.
Data centres top the list of growth opportunities
In robust, yet heterogenous world BACS market.
Increased funding for BSR announced
Within plans for next generation of new towns.
New Towns Taskforce interim policy statement
With initial reactions to the 6 month policy update.
Heritage, industry and slavery
Interpretation must tell the story accurately.
PM announces Building safety and fire move to MHCLG
Following recommendations of the Grenfell Inquiry report.
Conserving the ruins of a great Elizabethan country house.
BSRIA European air conditioning market update 2024
Highs, lows and discrepancy rates in the annual demand.
50 years celebrating the ECA Apprenticeship Awards
As SMEs say the 10 years of the Apprenticeship Levy has failed them.
Nominations sought for CIOB awards
Celebrating construction excellence in Ireland and Northern Ireland.
EPC consultation in context: NCM, SAP, SBEM and HEM
One week to respond to the consultation on reforms to the Energy Performance of Buildings framework.
CIAT Celebrates 60 years of Architectural Technology
Find out more #CIAT60 social media takeover.
The BPF urges Chancellor for additional BSR resources
To remove barriers and bottlenecks which delay projects.
Flexibility over requirements to boost apprentice numbers
English, maths and minimumun duration requirements reduced for a 10,000 gain.
A long term view on European heating markets
BSRIA HVAC 2032 Study.
Humidity resilience strategies for home design
Frequency of extreme humidity events is increasing.
National Apprenticeship Week 2025
Skills for life : 10-16 February
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?