Introduction to Fake Mansard Roofing
Most of the buildings in the historic neighborhoods of Washington DC have low slope or flat roofs. Flat roofs are very common in Washington DC because flat roofs allow buildings to be built closer together. Even 130 years ago, here in Washington DC, the city was built with a relatively high density.
The picture below shows a relatively common mixed use office and commercial building. At the top of the building, it looks like a standing seam metal clad mansard roof is built over the top of the front facade. That mansard roof is actually fake though. It’s not actually a roof at all. Instead it’s just a decorative ribbon built with metal panels that hide or conceal the mechanical equipment on top of the actual flat roof. If you look very closely in the picture below, you can see a single panel is missing which allows you to see straight through to the sky behind the panel system.
The next picture below shows that same view but more closely where you can see the ribbon of the panel system better.
For the sake of comparison, in the next picture below, we show an actual real mansard roof. This type of roof system is very common throughout Washington DC’s historic neighborhoods and happens to be clad with a slate, from the original time of construction roughly 90+ years ago. This building, shown below, like many, here in Washington DC, is a multi-unit building and the mansard is shared between two stairwell entries to the exterior of the building. The facade above the door to the left, in the picture, has a gable at the top.
A gable is the triangular portion of a wall between the edges of a sloping roof, typically seen in traditional pitched roof designs, but often used here in the historic parts of DC as well. Gable facades have been used in several different architecture styles: Queen Anne, Victorian, and even Carpenter Gothic styles of architecture, and many other architectural styles.
The next picture below shows similar buildings on the left side, but the buildings on the right side have no mansard at all. Other than this difference, the buildings are actually built very similarly. Basically, the building’s on the left have a mansard roof and instead the buildings on the right just have the brick facade built up higher in a straight vertical line.
It’s hard to say exactly which one looks better and which one looks worse, these two different styles are just basically different. The buildings built without a mansard look a little bit more plain and basic but the ones built with a mansard also can in some cases look a little bit more like a basic country house which is also a bit boring. Like the buildings on the right hand which share a continuous front wall without separation or division, the two buildings on the left basically share a planar roof substrate. Their roofs continuously join to one another.
In contrast to the buildings shown in the picture above, the picture below shows different buildings with a similar flat front wall except the building in the center has an elaborate black painted cornice. Almost nothing is shared between these three buildings, they’re built at different facade heights and they do not share almost any elements. They do however have demising walls that straddle or sit directly on a property line though. The two buildings on the right have an elaborate decorative cornice made from pressed sheet metal, but the building on the left has a corbelled masonry cornice made from brick.
They join the roof at the top of the facade. In most cases, a low slope or flat roof will begin at a point that projects just beyond the top of the cornice with a metal termination. In most cases that metal termination will either be a gravel stop or a drip edge. At that point, the low slope or flat roof membrane will connect to that metal termination and from that point, the roof will run continuously as a low slope membrane.
There are many different types of roof systems used for low slope configurations. Some of the most common roof membranes are modified bitumen, TPO, EPDM, and PVC. Modified bitumen is clearly one of the most prolific and common types, but TPO membranes generally perform better with lower upkeep and maintenance cost.
In this coming weeks blog article we will look at more examples of mansard roofs and a closer view of the fake mansard roof shown above. Will also talk about some of the materials used for copings at the sides of these roofs and explain some of the differences between historic and contemporary flashings and copings.
We recommend every building owner in DC who values the longevity of their roof (and their investments) and building use a contractor who values the simple and important principles of proper roof construction like Dupont Roofing DC. Learn more about our company and the proper techniques of working with roofing on historic buildings in Washington DC here on our blog at DupontRoofingDC.com, and you can call us at (202) 840-8698 and email us at dupontroofingdc@gmail.com. We are happy to help and at least talk through options.
