In the simplest form, a mansard roof is a combination of a gambrel and hip roof in terms of design, and it’s also called a curb or French roof. If you’re not 100% sure what a gambrel roof is, it’s a modified form of the gable roof, but until the gable roof, it has two slopes on each side of the design.
Mansard roofs are a perfect example of how architectural design is much more than creating something for the best functionality possible; it’s also an art form. Pierre Lescot was first credited with creating this roof style in the 16th century, and it exploded in popularity in the 17th century, thanks to Francois Mansart. It quickly became a fundamental part of French architecture, and you can see it in many countries around the world. But, how do you identify this roof style?
Mansard roofs were very popular centuries ago, but due to how difficult they are to build and maintain, they have slowly fallen out of popularity.
Mansard Roof Style: Brief History
Francois Mansart is remembered as the Father of French Architecture, but he also had a very practical design for this roof as well. The point of the dual-pitch mansard roof was to be able to put a full floor of living space above the building’s cornice line without increasing the technical number of stories a structure had. This made it very appealing from an economical standpoint in a packed city like Paris where upward mobility in buildings came with heavy taxes and restrictions.
The top of the mansard roof design generally has a flat and broad look to help maximize the spatial volume under it. Think of it as a hipped roof with the top surface that spreads almost to the building’s edges. The lower pitch can curve or flare inward (concave), curve outward in a bell or S-shape (convex), or it can angle very steeply. The roof itself can be two stories high in some instances.
No matter the exact roof shape, mansard roofs always have several dormer windows to help light up the living space. Mansard roofs and Second Empire features are usually found together in the design style itself, and these all fall under the mansard roof umbrella. It’s true that every Second Empire home has a minimum of one mansard roof or more, does having this roof always mean the house is Second Empire? Technically speaking, no.
With Second Empire buildings, this roof has to be the defining feature instead of a secondary one. For example, you may have a Queen Anne-style house with a gabled main roof and a tower with a mansard roof. This house style is still a Queen Anne instead of a Second Empire. In the same vein, a lot of Stick-Style houses have these roofs, but they don’t fall into the Second Empire classification because the Stick-Style dominates the design. Periodically, single-story mansard houses will show up, but this is a minority.
Just as quickly as it happened, this French influence faded very rapidly in the architectural industry in the late 19th century in America. When France’s money dropped after the Franco-Prussian War, which was disastrous for the French, the prestige of French things declined. Also, the rapidly-growing ranks of American architects were determined to find their own architectural designs. So, houses and buildings started to go toward other styles while keeping the very distinct mansard roofline.
The other popular design styles of the day, including Queen Anne, Italianate, High-Victorian Gothic, and Romanesque all caught the house building public’s attention, and they all used small parts of the Second Empire decorations as well as the mansard roof.
Second Empire Style
In the United States, the first true Second Empire-style building was Washington DC’s Renwick Gallery that was completed in 1859. It’s now an important part of the Smithsonian Institution Museum of American Art, and it was originally built to house the huge private art collection of millionaire William Wilson Corcoran. It was co opted as a government office building during the Civil War. The owner got it back for a short period of time before it was returned to being a government building. James Renwick, the architect, also designed the Castle on the Washington Mall.
A lot of historic buildings come with the mansard roof installed because it was very popular at the time architects built the space.
You may hear the Second Empire design referred to as the General Grant Style because it was very popular in the United States after the Civil War during Ulysses S. Grant’s presidency. President Grant was responsible for calling Alfred B. Mullett, the Architect of the Treasury, to design his State, War, and Navy Building by the White House. This is the building that made this architect famous and it fueled a boom in French architecture among the super-wealthy entrepreneurs in the postwar time who made their fortunes in the timber, railroad, mining, land speculation, and iron production industries.
The new availability of trained architects from across the country and the presence of greater wealth were the two driving factors that pushed the Second Empire to a nationwide American style. Transportation advances like the Transcontinental Railroad and printing advances were other reasons why this style spread so quickly.
Like Mullett and Renwick’s public buildings, high-end Second Empire house styles had a huge amount of fancy ornaments, especially concentrated around doorways and windows. While elaborate surroundings around the doors and windows in masonry weren’t unheard of, cast-iron decorative elements replaced stone. Paired columns, one-story columns, and pilasters perched in multiple layers from the bottoms and tops of these designs. It’s common to see a large amount of classical ornaments.
The Second Empire style wasn’t an entirely practical style for a person who had a limited budget. However, the mansard roof was very useful, both to help you add visual distinction and heft to a simple or small building and to secure more living space on the top of your building. In turn, this is what caused the popularity of mansard roofs to spread. You could make a single-story home dignified by adding a mansard roof to it.
If you take a glance around the historic districts in the United States, you’ll find the Second Empire style very commonly as historical house styles. It wasn’t an easy house style to maintain or build and this is one of the biggest reasons why mansard-style mansions have turned into public buildings or museums. Even though it was short-lived, this style was among two or three of the most striking home designs in America. You could find it in urban spaces in the very early suburbs, and it was also in country estates.
Defining a Mansard Roof
The mansard roof style is a cross between gambrel roofs that have dual angled roof sections on both sides and a hip roof that features angles on all four sides. In short, this style has two slopes on each side, and the bottom slope gets pitched at a sharper angle than the upper one. Just like the hip roof style, mansard roofs are four sided.
Types of Mansard Roofs
To date, there are four common types of mansard roofs that you can choose to have when you build your home. They are:
- Concave – This roof design has a flat upper slope with a steeper lower slope that has an inward curve. This style won’t give you as much space as other mansard roof styles, but it has a very rich architectural heritage as was seen on historic buildings and mansions.
- Convex – This style features a lower slope that has an outward curve. It resembles a bell-shaped curve, and it gives you a large amount of extra space in your attic areas.
- S-Shape – This roof is a combination of the concave and convex roof line styles. It starts with an inward curve and finishes with an outward curve.
- Straight – Finally, this type of mansard roof has an almost vertical, long slope over a smaller top slope. You can’t always see the upper slope from the ground level. A lot of roofs with this style have dormer windows to allow ventilation and natural light to the upper floor.
There are a few different types of mansard roofs you can choose from, and some may fit your situation and needs better than others. Large Mansard Roofs by Matt Gibson / CC BY-NC 2.0
Mansard Roofs – Important Things to Know
Now that you know what a mansard roof is and the four styles you can get, there are a few more important things you need to know about. They include:
1. You Get the Steepest Pitch a Roof Can Have
While a mansard roof isn’t vertical, it’s as close as it gets. So, this roof offers the steepest pitch you can get. But, what is the pitch of the roof? Roof pitch is the steepness or angle of the roof. The pitch is the ratio that you calculate by the number of inches or feet it rises for every foot or 12 inches it extends out horizontally. For example, if your roof has a 6 ½ pitch, it will go up six inches or feet for every six feet or inches it goes out. Due to this steepness, mansard roofs are the opposite of low slope roofs. However, they have something in common. You can’t use asphalt shingles on either type of roof, and we’ll explain why below.
2. Don’t Use Asphalt Shingles on Mansard Roofs
Asphalt shingles don’t work well with this roof style. Installing shingles onto a mansard roof is a little like hammering them to a wall. The weight of these shingles is far too heavy to put them at the pitch of this roof. Because of this, it’s virtually impossible to stop the shingles from slowly sliding down the vertical sides of the roof. Even if you follow the manufacturer’s instructions exactly as they have them, the shingles will slowly start sliding down.
While your roofing contractor will do everything they can to stop this from happening, like using 10 to 12 nails with sealer, this won’t stop the shingles from sliding. However, you should note that just because asphalt shingles aren’t a good fit doesn’t mean you can’t install them.
3. Pick the Right Shingles for Your Mansard Roof
Now you know why we don’t recommend asphalt shingles on this type of roof. But, which shingles will fit? There are two main options most contractors recommend for mansard roofs, including cedar shake shingles or synthetic shingles. Synthetic shingles feature recycled plastic as the main material that look like cedar shake or slate shingles. They’re a premium type of shingle, so they’re much more expensive than asphalt shingles. They won’t slide down your vertical mansard roof. Cedar shakes are the second type of shingles, and they feature a natural wood material in the makeup.
Instead of hammering individual cedar shake-style shingles onto the vertical sides of your mansard roof, you make a strip of six cedar shakes and install them as panels. The panels give the look that you installed each shingle separately. These are also more expensive than asphalt shingles, so it’ll be up to your budget to help you decide what you can and can’t afford to put on your roof.
Mansard Roof Benefits
There are several benefits to having a mansard roof as your home’s roof style, and they also come with drawbacks. They include but are not limited to:
One of the biggest advantages of installing this roof style for your commercial building or home is that it gives a very elegant look. It has a sophisticated appeal with an aesthetic look that is due to the fact it started in the Renaissance period and was a huge part of French architecture. To date, buildings and homes with this roof are as elegant-looking as they were back in the 17th century.
Extra Attic/Loft Space
Due to the fact that this roof has a virtually vertical bottom slope design to it, it offers more attic space than gable or hip roofs. Even better, this roof’s loft area has so much space that you can put it in a master bedroom if needed. This is a nice luxury for any home, and the added dormer windows will also enhance the ambiance of the room while allowing more natural light in.
If you plan to expand your living area by adding more floors or stories to your home, installing a mansard room makes it easier. As we touched on earlier, the structure of this roof gives you more space to use and makes it less complex if you plan on adding more room or living spaces to your current home without having to install a full new addition.
Due to the expandability and the additional space you get, mansard roofs work well in urban and rural areas. This is especially true for commercial buildings since it makes adding floors easier and quicker.
Improved Heat Distribution
The natural expandability and added windows give you excellent heat distribution throughout the whole building, and this makes it more comfortable. Also, having great heat distribution allows you to lower your heating costs.
Even though they have benefits, these roofs also come with drawbacks. Knowing both will help you decide if this is really the roof style you want or if you should go with something else. Mansard Roof Benefits and Drawbacks by Don Shall / CC BY-NC-ND 2.0
Mansard Roof Drawbacks
Just like benefits, mansard roof styles do come with some drawbacks, and it’s essential that you know both the good and the bad so you can make an informed decision.
We’ve talked about how the structure, style, and look of mansard roofs are all benefits of having it, but the price you pay to get this roof is very steep too. Because these roofs have two slopes on each side and it uses a hybrid form of a gambrel and hip roof, you can see how the installation process can be complex. This drives up your installation costs. Also, since there are very few roofing contractors who have experience with installing this roof type, this increases the costs even more.
High Maintenance and Repair Costs
The repair costs for your mansard roof can easily be just as high as the original installation costs. This roof type is very vulnerable to issues with rain and snow, and this is both expensive to repair and hard to maintain. Also, finding roofing experts that are qualified to perform these repairs is challenging. As a result, this increases your roof repair and maintenance costs.
Not Great Weather Resistance
Mansard roofs don’t cope very well with exposure to heavy rain or snow due to the fact that it has a flat upper pitch in the design. Not only can this lead to water leaks in the roof, but it can also cause the entire structure to collapse due to the snow’s weight.
Tough to Get a Permit
Depending on the taxes, your location, requirements, the limitations or restrictions can vary. You could have height restrictions with higher taxes if you install a mansard roof instead of a more traditional design. If you plan on installing this type of roof, you want to look at local laws before you start the construction process.
A mansard roof is a very elegant and sophisticated addition to your home that can easily give you more living space, but it also comes with some very important benefits and drawbacks to consider. If you believe that this is the roof style you want, do your research and look for experienced local contractors to pull it off.
Jen is a master gardener, interior designer and home improvement expert. She has completed many home improvement, decor and remodeling projects with her family over the past 10 years on their 4,500 sf Victorian house. She is also a passionate farmer who keeps goats, chickens, turkeys cows and pigs on her farm, and an instructor for her community’s Organic and Sustainable Farming project.