Complete Guide to Mansard Roofs: Cost, Styles, Pros & Cons

What Are Mansard Roofs?

Mansard roofs, also called French or curb roofs, are known for their classic, boxy shape and steep lower slopes. Each of the four sides features two distinct slopes: a nearly vertical lower slope and a gentler upper slope that’s often hidden from street view. This style isn’t just eye-catching, it also creates more usable space in the attic or top floor of the home.

Popularized during the French Renaissance, mansard roofs remain a go-to option for homeowners looking to blend timeless design with added functionality.

History of the Mansard Roof

The mansard roof dates back to the mid-1500s, with one of the earliest examples found in the Louvre’s southwest wing in Paris. Its rise in popularity is credited to architect François Mansart in the 1600s, whose use of the style in elegant urban architecture helped make it iconic. His great-nephew, Jules Hardouin-Mansart, carried the trend into grand designs like the Palace of Versailles.

Today, mansard roofs are still found on historic homes across New England and are making a comeback in modern, upscale builds.

How Much Does a Mansard Roof Cost to Install?

Installing a mansard roof is a more involved process than standard roof styles, and that complexity is reflected in the cost. For a 2,000-square-foot home, expect to pay $16,000 to $40,000, or about $8 to $20 per square foot.

Your total cost will depend on:

• The size and shape of your roof
• The materials you choose
• Local labor rates
• The need for dormer windows or structural changes

Switching from a different roof style will typically require additional framing and custom features, which can increase your budget.

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Best Roofing Material for a Mansard Roof

Because mansard roofs feature steep slopes and sometimes flat tops, it’s important to choose the right materials for both function and aesthetics.

Steep Lower Slopes:

• Slate tiles and wood shingles are traditional, offering a classic look.
• Synthetic shingles mimic slate or wood but are more affordable and lightweight.
• Metal roofing provides durability and a modern touch.
• Luxury asphalt shingles are another option, but installation must be secure due to the slope.

Flat or Low-Slope Tops:

Use waterproof membranes like EPDM, PVC, or TPO. These materials resist pooling water and work well on low-pitch areas that need extra protection.

What Are the Best Roofing Materials?

Wondering what roof material is best for your home? This is the place to start.

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Benefits of Mansard Roofs

Mansard roofs combine style and function in a way that’s hard to beat. Here are the top benefits:

Elegant Curb Appeal

The signature shape of a mansard roof adds sophistication to any home. This classic look is ideal for homeowners who want to boost property value and create a lasting impression.

Added Living Space

The steep lower slopes maximize interior space. Whether you finish it as a bedroom, office, or guest suite, the attic becomes far more functional.

Built for Dormers, Light, and Expansion

• Dormer windows fit perfectly and brighten the upper floor.
• Natural light creates a more comfortable living space.
• The vertical design allows for easier home expansions down the road.

Potential Drawbacks

While beautiful and functional, mansard roofs come with a few challenges:

Snow and Water Buildup

Because of the flatter upper slope, snow, rain, and debris may collect over time. Without proper drainage or membrane protection, this can lead to leaks or roof damage.

Permit and Design Complexity

Installing a mansard roof may require extra permits or design approval, depending on your location. The complex structure also means not every roofer will have the experience to build one properly.

Higher Costs and Maintenance Needs

From the start, a mansard roof will cost more than simpler designs. Repairs and inspections also tend to be more expensive due to the roof’s steep angles and materials.

Styles of Mansard Roofs

Not all mansard roofs look the same — there are a few distinct styles, each with its own visual appeal and design benefits. Here’s a quick breakdown of the most common ones:

Straight

This is the classic version most people picture when they think of a mansard roof. It features a steep, straight lower slope paired with a nearly flat upper section. It’s a great option if you’re looking to add dormer windows and create a roomy attic space.

Concave

With a lower slope that curves inward, the concave style softens the overall look of the roof. It’s a more decorative option, often seen on grand, 19th-century homes that aimed for a bit of drama in their architecture.

Convex

This version curves outward at the base — think of it like the shape of a bell. That rounded look not only adds visual interest but also makes room for more interior space. You’ll often find this style on historic buildings and older public structures like courthouses.

S-Shaped

Blending the inward and outward curves of concave and convex designs, the S-shaped mansard roof offers a flowing, graceful profile. It’s a favorite for custom builds or high-end homes where a bold architectural statement is part of the plan.

Mansard vs. Gambrel Roofs

Mansard and gambrel roofs are often confused because of their shared double-slope design. However, they differ in key structural ways, especially when it comes to how each roof covers the home and the architectural elements involved. One of the biggest differences? Gambrel roofs use gables, while mansard roofs use hips.

Mansard Roof

The mansard roof offers a formal, symmetrical look with a four-sided design. It’s an ideal choice for homeowners who want to maximize upper-floor space while adding a refined, architectural touch to the exterior.

• Structure: Features two slopes on all four sides. The lower slope is steep, almost vertical, while the upper slope is shallow or flat.
• Sides: Fully hipped, meaning all four sides slope inward with no vertical walls or gables.
• Style: A staple of French Renaissance and Second Empire architecture. Dormers are often added for light and ventilation.
• Benefits: Creates more usable attic or top-floor living space and allows for complex, elegant detailing across the entire roofline.

Gambrel Roof 

The gambrel roof shares a similar two-slope concept but only on two sides. The upper slope is gentle, and the lower slope is steep, creating a barn-like shape. This style is more informal and commonly found in American homes and rural architecture.

• Structure: Two sides with double slopes; the steeper lower slope maximizes space, and the flatter upper slope improves runoff.
• Sides: Ends in vertical gables on the other two sides, unlike the mansard’s hipped design.
• Style: Common in Colonial, Dutch Colonial, and farmhouse-style homes. Adds classic charm and a bit of rustic appeal.
• Benefits: Easier and less costly to construct than mansard roofs. Still offers generous attic space and is perfect for dormers or lofts.

Finding a Quality Roofer

Mansard roofs aren’t something just any contractor can handle. The unique framing, steep angles, and added materials require specialized knowledge and experience.

Modernize makes it easy to connect with professionals who know this style inside and out. We’ll match you with up to four licensed local roofers who can help you plan and build your mansard roof the right way, from start to finish.

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