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Mansard Roof

Average cost range:

$16,000 - $40,000

On average, the cost to build a new mansard roof on a home costs $16,000 to $40,000, or $8 to $20 per square foot for a 2,000 square foot home, depending on the roof materials you choose. The total cost can also vary depending on the size of the roof and average local contractor rates.

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Homeowners exploring options for their next roofing project or new build might be intrigued by one of the most classic roof styles around—the mansard roof. Also known as a French roof or a curb roof, this style is known for its unique appearance that draws heavily from European styling and traditions. In this article, we’ll walk you through everything you need to know about mansard roofs, from their history to their cost and benefits for homes today.

History of the Mansard Roof

The history of the mansard roof dates back to as early as the mid-16th century when the style was first used in buildings across Europe. One of the earliest examples of the style is seen in the southwest wing of the Louvre’s main square, designed by Pierre Lescot.

Mansard roof style - Modernize

However, it wasn’t until the 17th century that they boomed in popularity and became the namesake style of French architect François Mansart. The mansard style became so popular that it was adapted by François’ great-nephew, Jules Hardouin-Mansart, when designing a portion of the Palace of Versailles. 

Now, you can find mansard style roofs on homes across America, especially in New England.

What is a Mansard Roof?

The primary features of a mansard roof are two slopes on each side. The more prominent lower portion is sloped typically at 70 to 80 degrees and includes dormer windows—which helps increase the amount of attic space in the building. The upper portion features a greater pitch angle, typically around 35 degrees, and is often not visible from the street level.

Mansard Roof

Historical style roof popular in New England homes with two slopes on each side

  • Rustic charm

  • Dormer windows add natural light

  • More attic space, which can be converted into an extra room

  • Various material options

The style can be made of nearly any roofing material. However, they are traditionally finished with slate tiles or wooden shingles—adding to the historic aesthetic. Other shingle or tile materials, such as asphalt shingles or metal tiles, can also be used to lower costs or improve the roof’s durability.

Mansard Roof vs. Gambrel Roof

Mansard roofs are often confused with another similar style roof—the gambrel roof style.

A key element of a mansard roof is the incorporation of the gambrel style—with both featuring a prominent, two-sloped design in which the upper slope is less steep and shorter.

However, gambrels are actually a type of gable roof, which feature slopes on two sides and gables on the other two sides. Gables are vertical extensions that reach the top ridge of the roof. A mansard roof lacks these gables.

Another key element of a mansard roof is the use of hips. Hip roofs have slopes on all four sides and feature a horizontal ridge along the top—something that mansard roofs lack.

Types of Mansard Roofs

Much like other roofing styles, not all mansard roofs are identical. There are several common types of mansard roofs, each with its own unique features and pros and cons. Here’s a quick look at some of these common types.

mansard roof

Straight mansard roof

This design boasts a subtle slope on the upper panel and a lower slope that is almost entirely vertical. Straight mansard roofs typically feature dormer windows, which provide ventilation, light, and additional attic space.

The nature of the straight design, however, does come with a drawback. Snow and rain can pool on the roof, weighing it down. This can eventually lead to cracking, leaks, or other roof damage over time.

Convex mansard roof

A convex mansard roof features an outward curve on its lower slope that looks like either an S or a bell. This outward curve allows for additional interior space without the need for additional floor additions. This type of design is most commonly used in the construction of courthouses.

Concave mansard roof

The opposite of a convex roof type, a concave mansard roof features an inward curve that occasionally flares. The roof type also has a bottom slope with a steep angle. This type of mansard roof is typically found on large buildings (such as home mansions) that were built in the late 19th century.

Much like their straight counterparts, concave mansard roofs tend to allow for snow and rain accumulation due to their flatness.

For straight and concave mansard roof styles, it is recommended to have annual inspections performed by a roofing professional to ensure no damage is present.

How Much Does a Mansard Roof Cost?

Mansard roofs are a complex roof style to design and install, and this complexity is reflected in its higher cost. Similar to other roof styles, the cost of a mansard roof replacement or installation is dependent on several factors, including:

  • Types of materials used
  • Size of the roof
  • Your home’s geographic location

On average, homeowners with a 2,000 sq. foot home can expect to pay between $16,000 and $40,000 for a mansard roof framing, or $8 to $20 per square foot. These costs can increase if more premium materials are used, such as slate shingles, or if the construction of dormer windows is required (which would be the case for homeowners converting their home to a mansard roof from a different roof style).

Because costs can vary depending on your home’s specs, we recommend using our Cost Calculator tool to get a closer estimate suited to your specific project.

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Pros and Cons

Despite its high cost, there are several benefits homeowners can gain from having a mansard roof. Let’s take a look at some of the pros and cons of this roof style.


  • A highly aesthetic style that can add a great deal of curb appeal and home value.
  • The design allows for added attic space, often enough to be used for an additional bedroom.
  • The inclusion of dormer windows brings additional natural light into the home. 
  • The style is much easier to expand upon compared to other roof types. This makes it a great decision for homeowners that might want to build a home addition down the line.
  • It is classic style, so it can easily blend-in in both urban and rural neighborhoods.


  • Some designs can make it difficult to move snow and/or rain from the roof. This can lead to cracking or leaking over time.
  • The complexity of the roof makes it more expensive than many other roof types to install, maintain, and repair.
  • Its complexity also means that there might be fewer roofing experts in your area who can take on such a project.
  • Depending on your location, mansard roofs can be difficult to get permits for and to conduct inspections on.

Starting Your Roofing Project

Few roof styles are as classic and elegant as a mansard roof. If you are ready to move forward with your roofing project or need some more insight before doing so, the pros at Modernize can connect you with local experts to make the process as simple as possible.