What is a mansard roof?

What this means for your home project

1. Compare old photographs of the house with its current roof; note missing details to discuss before restoration work. Source: National Park Service, read 2026-11-03.
2. Request a written appraisal of the roofing material’s existing condition and quality; use that appraisal as the starting point for the repair discussion. Source: National Park Service, read 2026-11-03.
3. Request detail drawings or a sample mock-up with the proposed scope; ask for a reply that shows the project’s special roof details. Source: National Park Service, read 2026-11-03.

What style house has a mansard roof?

The roof appears on older Second Empire buildings and on the later Mansard style. Washington’s preservation guide describes 1960s and 1970s examples as typically two stories, with the upper story hidden behind the steep roof. That later style also appears on single-family homes, duplexes and apartments. “Named after its distinctive roofline, the Mansard style is a re-interpretation of the Second Empire style, which was popular a century earlier.” Source: Washington State Department of Archaeology and Historic Preservation, read 2026-11-03. “Mansard style buildings of the 1960s and 1970s are typically two stories in height, although one story versions can be found.” Source: Washington State Department of Archaeology and Historic Preservation, read 2026-11-03. “The second story is “hidden” by a steeply sloped “mansard” style roof that extends to the top of the first floor.” Source: Washington State Department of Archaeology and Historic Preservation, read 2026-11-03.

What about handling problems with drainage from an upper roof on a mansard style?

Include the upper roof’s drainage in the assessment. Washington’s Mansard guide describes a flat or nearly flat roof behind the steep face. For historic roofing, the National Park Service identifies blocked gutters and downspouts as a route for water to back up beneath the roofing units. “Behind the mansard, is a flat or nearly flat roof.” Source: Washington State Department of Archaeology and Historic Preservation, read 2026-11-03. “The gutters and downspouts need periodic cleaning and maintenance since a variety of debris fill them, causing water to back up and seep under roofing units.” Source: National Park Service, read 2026-11-03.

Should I repair or replace an aging mansard roof?

Assess the existing material and the extent of the work before choosing replacement. For a historic slate mansard, National Park Service guidance distinguishes replacing individual slates from replacing flashing, the metal at roof joints: the latter can require substantial removal of surrounding slates. Standard 6 favors repairing deteriorated historic features. “Individual slates can be replaced normally without major disruption to the rest of the roof, but replacing flashing on a slate roof can require substantial removal of surrounding slates.” Source: National Park Service, read 2026-11-03. “Strips of sheet metal bent to fit the angle between any two roof surfaces or between the roof and any projection, such as a chimney.” Source: New York City Landmarks Preservation Commission, read 2026-11-03. “Deteriorated historic features shall be repaired rather than replaced.” Source: National Park Service, read 2026-11-03.

How can we modernize a mansard roof?

For a historic mansard, plan updates around retaining its distinctive features. The Secretary of the Interior’s Standard 5 calls for preserving features that characterize the property. Where deterioration requires replacement, Standard 6 calls for matching the old feature’s design, color, texture and other visual qualities, and materials where possible. Apply these historic-rehabilitation standards when discussing a proposed material change. “Distinctive features, finishes, and construction techniques or examples of craftsmanship that characterize a historic property shall be preserved.” Source: National Park Service, read 2026-11-03. “Where the severity of deterioration requires replacement of a distinctive feature, the new feature shall match the old in design, color, texture, and other visual qualities and, where possible, materials.” Source: National Park Service, read 2026-11-03.

What are the problems with roofing materials cracking or slipping out of place on the mansard roof?

The cause depends on the covering. National Park Service guidance for historic roofing says tile can crack from impacts or improper foot traffic; it cannot support much weight. The same brief explains that pressure from ice floes can dislodge slates, shingles or tiles. Start a professional assessment with the material’s existing condition, rather than assuming every steep roof has the same defect. “Tiles will weather well, but tend to crack or break if hit, as by tree branches, or if they are walked on improperly.” Source: National Park Service, read 2026-11-03. “Like slates, tiles cannot support much weight.” Source: National Park Service, read 2026-11-03. “The pressure from these ice floes will dislodge the roofing material, especially slates, shingles, or tiles.” Source: National Park Service, read 2026-11-03. “A thorough examination of the roof should start with an appraisal of the existing condition and quality of the roofing material itself.” Source: National Park Service, read 2026-11-03.

Sources

• Glossary: Mansard, Dormer and Flashing — New York City Landmarks Preservation Commission; read 2026-11-03.
• Architectural Style Guide: Mansard — Washington State Department of Archaeology and Historic Preservation; read 2026-11-03.
• Preservation Brief 4: Roofing for Historic Buildings — National Park Service; published 1978; read 2026-11-03.
• The Secretary of the Interior’s Standards for Rehabilitation — National Park Service; published 2026-09-02; read 2026-11-03.