Mansard Roof Types – Part II

Part 2 of Mansard Roof Types

In a recent article, part of three-part series, we took a look at several different types of mansard roofs, typically found at Capitol Hill and Washington DC type rowhomes. 

Read part 1 here

Not all rowhomes have Mansard roofs, there are alternative styles such as roofs and facades meeting just at cornices and even relatively simple flat faced facades, but somewhat elaborate mansards are common at DC’s most elegant historic brick rowhomes.  These buildings generally have a flat or low-slope roof covering the remainder of the building.

Material and style options of a mansard roof

Above, we listed some of the most common types of materials used in mansard roof construction at historic buildings, but material or finish types are not the only variable options available and which must be selected in the design, there are also different layout options.  

The most common mansard roofs are high-sloped, running almost parallel but at an angle slightly countering the plane of the front facade, starting at a water table at the base, running upwards and terminating at a ridge at the top of the Mansard roof.  Other less common options include using dormers and or gables in the mansard.

Gables are flat / vertical ends that are generally triangular shaped under a roof ridge to enclose the area under the roof.  Dormers are small projections similar to gables, running in the middle of a mansard or additional roof in other types of buildings.

The picture below shows an example of a Mansard roof clad with asphalt shingles. Asphalt shingles are cheap roofing materials that can be used for pitched roofs, there are no restrictions in the basic building code against using asphalt shingles on a mansard roof, but historic areas may have restrictions to prevent this type of modern material from bastardizing the historic aesthetic.

mansard roof clad with asphalt shingles

Aesthetic value

Clearly, Mansard roofs have a much greater complexity and add a visual elegance and interest not found in more utilitarian flat front buildings.   The picture below shows a beautiful carved limestone dormer at the mansard roof of a historic masonry row building. The intricate detail in the carving shows an extreme level of craftsmanship. a crown at the top of the gable and the top of the dormer wall is carved into an egg and dart mould embellishment. Unlike a typical plaster mould though, this stone was not liquid poured or formed, it was hand carved. The perimeter of the gable is dressed in a copper sheet metal trim. The copper has oxidized over the past 100 years and now has a rich blue patina. Another stone carving area below the dormer and respective water table has a dentil cornice and a egg and dart carved relief. 

Masonry walls of the building, including the walls of the dormer itself, are built with a split face limestone.

aesthetically pleasing mansard roof

The gables at the matching pair of dormers, at the mansard roof, at the building shown in the photo below, are built with a tympanium style header. Stone dentil carvings border the underside of the stone headers at the triangular shape of the tympanums. 

tympanium style header

A closer view of a one of the single dormers at the mansard roof, follows below. The intricate detail of the architecture and masonry are beautiful. meanwhile, the adjacent mansard roof is clad with a cheap asphalt roof shingle. 

The next picture below shows a series of rowhomes built-in an alley type area of Capitol Hill.   As a counterpoint or a point of comparison, a picture of a typical row of buildings without a mansard shows a simple layout. This particular row is completely flat faced without front bays, cornices, or mansards.  The mansard has few strictly functional benefits, except it can skirt the rules of the zoning requirements to provide additional functional interior space by allowing parts of the area under the roof to possibly not count as an additional living level.   Mansard roofs were used extensively by an architect in France over 200 years ago to avoid having to comply with the same requirements and get more useful square footage out of the building. The style of these buildings, by comparison is quaint and simple, but they of course lack the elaborate ornamentation of the historic Mansard roofs of many other row homes in the Capitol Hill and Washington DC historic areas.

house without mansard roof

These houses happen to be super small but highly coveted because of their location near Eastern market.  The price of these houses happens to be astronomically high, over $1,000 per square foot, on average, at this current time, because of the high demand for houses in this city built with such low density and such a small housing inventory.   Considering the price per square foot, it wouldn’t be accurate to say that more elegant row homes built with elaborate historic details like mansard roofs are necessarily of higher value, but those houses are also larger and the price per square foot happens to be nonlinear (meaning the larger SF buildings often trend towards lower per SF value, ceteris paribus) in many cases in neighborhoods like Capital Hill and historic parts of Washington DC.

Maintainance of Flat Roof Systems

Smart proactive replacement, construction, upkeep and maintenance of low slope roof and mansard roof systems requires an enthusiastic interest and understanding of historical methodologies, waterproofing principles, and building science.   Here in Washington DC, historic and modern residential and commercial buildings are extremely expensive and the roof and related systems provide the shield that preserves the building. 

We encourage all of our clients, and all readers of this article and to our blog in general, to prioritize the value of quality construction and building maintenance, and develop a relationship with our company.  You can learn a lot more on our blog.  Feel free to check it out.  If you have questions about the roof and related systems of your building in Washington DC, contact us or fill out the webform below and drop us a line.  We will be in touch if we can help.

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