We recently took a survey of building and engineering characteristics of historic masonry row buildings. This is the first part of three-part series, we specifically took a look at several different types of mansard roofs, typically found at Capitol Hill and Washington DC type rowhomes.
The outline of the series follows:
- Common material types
- Material and style options of a mansard roof
- Aesthetic value
- Added elements and why less is more
- Anatomy of a Mansard Roof
More than anything else, our company focuses on the repair and replacement of low slope or flat roofs in the historic neighborhoods of Washington DC such as Capitol Hill and Dupont Circle. Today, however, we are taking a closer look at the common Mansard roofs above the front facades of many Washington, DC rowhomes.
Common material types
The picture below shows an example of a historic mansard roof at the front facade of a historic row building. This particular mansard roof has two dormers, the mansard roof is clad with a gray terracotta clay tile. This is a kiln fired clay material, similar to brick but formed and shaped in a concentric pattern that can be overlaid in succession, similar to a roof shingle. The Dormers at this roof are covered with a hip roof. A hip roof does not have an open or wall side like a gable roof. The hip roof has a continuous eave at all perimeter sides.
Our company also repairs and or replaces these Mansard roofs as well. Generally Mansard roofs are built from material types that are totally different than typical flat or low-slope roofs. Some examples of common material types follow:
Materials commonly used for low-slope roof systems:
- TPO (Thermopolyolefin)
- Modified bitumen
- Standing seam metal
- Ballasted BUR (Built-up roof)
Materials commonly used for mansard roof systems:
- Slate shingles
- Terracotta tiles
- Cedar shake shingles
- Asphalt shingles
- Synthetic slate shingles
It should be noted that:
- Cedar shake shingles are RARELY, if ever used on rowhome Mansard roofs, in urban areas because of the building code related to material combustibility and fire prevention. This same trend and understanding of fire prevention, related to cladding was understood as far back as the time of the original construction.
- Asphalt shingles are commonly used but should be banned or prohibited from use in almost any Washington, DC area where historic integrity is valued.
In the next photo below there a portion of the demising wall, with an extending parapet with a coping covering. This parapet separates the two row buildings. The dormer at the right is a bay style dormer.
A very hard to reach area between the two dormer roofs has a missing terracotta tile. this type of roof repair is possible but complicated by the challenges related to access.
Maintaining 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 fill out the webform below and drop us a line. We will be in touch if we can help.