Scupper rain conductor heads are a component of the drainage system for flat roofs, particularly in larger commercial or residential buildings in Washington DC. Downspouts, gutters, and rain leaders go together with a roof system but they’re not actually a part of the roof system itself so they’re often overlooked or forgotten in overall planning. We encourage our customers to take this part of the building into consideration too when they’re planning the long-term reserve study for the building. Unlike smaller flat roofs found on historic row homes, which often have a single rear low termination point leading directly to a gutter, larger flat roofs, or urban (DC) row homes with a chopped up configuration or layout with a complex series of additions inline often require a more sophisticated drainage solution.
Scuppers are openings or perforations in the exterior parapet walls of the building, designed to allow water to flow out from the flat roof surface. These openings are connected to impermeable sleeves or sealed pipes that extend through the parapet wall and lead to a scupper rain conductor head on the exterior. The conductor head collects the rainwater discharged from the scupper and directs it down through a downspout, allowing proper drainage and preventing water accumulation on the roof.
In some cases, scuppers are installed as an emergency overflow system, positioned above the height of the intended primary drains. A redundant setup like this acts as a safeguard, allowing excess water to escape in the event that the primary drainage system becomes overwhelmed or obstructed. Unlike the most common typical historic row homes, buildings that are built with larger layouts or facades on several sides of the buildings might not have an open rear termination. In a case where a building roof is bounded on all sides by a parapet, scuppers may be the only way water can drain away from the roof. Unlike an open side of the building though, scuppers themselves are just comparatively very small holes. If and more likely when they become clogged from tree leaves or other debris, the rooftop can fill up with water like a swimming pool and the weight of that water can literally cause a building roof to collapse. Therefore, it’s very intelligent planning to have redundant backup scuppers to work as overflows built at a height above the regular scuppers. In most cases when you see a redundant backup Scupper as an overflow, the scupper will not have a downspout or conductor head installed, instead it’ll just be a wide open hole at the parapet side.
A typical scupper rain conductor Head system consists of several key components. First, the scupper itself is a opening in the parapet wall, occasionally featuring a flange or lip to prevent some debris from entering the drainage system. An impermeable sleeve or pipe extends through the wall, providing a pathway for water to flow from the roof surface to the exterior. This part of the building is called the scupper. It’s very similar to a scupper in a ship deck.
On the outside of the building, the scupper rain conductor head is installed, typically built from durable or water / moisture resistant materials such as cast iron, copper, or aluminum. The conductor head features a basin or receptacle to collect the water discharged from the scupper, as well as a downspout connection to channel the water away from the building and into the appropriate drainage system.
Flat roofs are a particularly common in Washington DC’s architectural landscape, this reflects both the city’s history and the practical requirements for building in a dense urban environment.
The prevalence of flat roofs in DC architecture can be attributed to several factors. Washington DC was built with a relatively high density, particularly in its historic neighborhoods, where row homes and buildings were constructed side by side, with little to no space separating them. In such a tightly packed urban building footprint configuration, building with pitched roofs would have been impractical and posed significant challenges for installation and maintenance. In simple terms the buildings are tall and slender and with restricted (or zero access in some cases) access from the sides, it is hard to reach the roof and extremely dangerous to work on them.
Flat roofs are more practical solution, allowing buildings to be constructed side by side without the need for excessively high demising walls, which would have been necessary to accommodate the slope of pitched roofs. This approach not only saved construction costs but also provided better fire separation between adjacent structures.
The parapets, the low walls that extend above the roof’s surface, play a role in improving fire safety. In the event of a fire, the parapets acted as barriers, like a physical shield, preventing flames from spreading laterally from one building to another, a significant concern in densely built areas.
Additionally, the accessibility challenges associated with pitched roofs in a side-by-side configuration of row buildings contribute to the prevalence of flat roofs in Washington DC. Pitched roofs in such a configuration would have been extremely difficult to access safely for installation and maintenance purposes, as there would be no clear path or space between buildings.
In contrast, flat roofs offered a more accessible solution, allowing workers to safely access the roof surface for repairs, maintenance, or modifications without the need for specialized equipment or precarious setups. This accessibility is particularly important in the city’s historic neighborhoods, where accessing the rooftop is required for several reasons. Not only is routine maintenance and upkeep required on flat rooftops, but often today the internal heating and cooling systems of our buildings have been modernized and the roofs are often used for locations to store the modern HVAC equipment.
While flat roofs were initially driven by practical considerations, they also became an integral part of Washington DC’s architectural character, contributing to the distinctive streetscapes and skylines that define the city’s historic districts and neighborhoods. Scuppers, in many cases, are required to make these flat roofs work and function properly so they can drain water effectively.
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.
