Story at a glance:
- Parapet roofs have been around for centuries. We outline the types.
- Including a parapet roof in modern building design comes with a host of benefits, from safety and privacy to aesthetics.
- Parapet roofs come in a variety of shapes and configurations these days.
A striking, modern roof design is a surefire way to make a building stand out. And though there are many ways to build a strong and beautiful roof, one common roofing technique has stood the test of time: the parapet roof.
Parapet roofs have been around for centuries and add both security and design flair to buildings.
If you’re wondering, “what is a parapet roof?” you’re in the right place. Let’s explore how parapet roofs have transcended time, plus the benefits that have solidified their design legacy.
What is a Parapet Roof?
A parapet is a low protective barrier that is an extension of the wall at the edge of a structure, such as a roof, balcony, terrace, walkway, or bridge. In a parapet roof a low barrier wall is erected from the roof itself.
A parapet roof’s main objective is to prevent those standing behind it from falling. Historically parapet roofs were used—dating back into ancient times—as a defensive measure atop castles, forts, towers, and city walls to keep invaders out.
Benefits of a Parapet Roof
Bellet Construction project at 141 Prince Street in New York. Photo courtesy of Bellet Construction
Although architects and designers may no longer use a parapet roof to protect buildings from invaders and secure city borders, parapet roofs come with other design benefits to strengthen buildings and improve their facades.
1. Parapet roofs increase roof stability and prevent wind-uplift.
When wind blows against a building, it can create what’s known as wind-uplift, where the pressure below the roofing system is higher than the air pressure above the roof. During high-wind periods, these pressure changes can be dramatic and weaken the roof system, eventually causing roof collapse.
One of the biggest benefits of a parapet roof is that it provides a barrier to wind, which can help mitigate pressure changes caused by wind-uplift and thereby fortify the strength of the roof.
2. They also help protect against other extreme weather.
Besides wind, a parapet roof can strengthen a building’s facade against hurricanes, thunderstorms, and other damage-causing weather. Parapet roofs also provide a barricade against storm debris like tree branches and block objects from coming onto the roof.
3. Parapet roofs increase occupant safety.
Just as a parapet roof protects a building, it can also protect those inside. When occupants are on the roof the parapet acts as a barrier to prevent falling from the building.
4. They offer fire protection.
In a parapet roof, the parapet extends above the roof plane. This can stop a fire from coming up the exterior of a building and immediately setting the roof membrane aflame.
5. Parapet roofs give buildings a unique design element.
Far from ancient battlements, modern parapet roof design has enabled architects to create parapet roofs in a variety of shapes and forms to align with any aesthetic. Parapet roofs can also make buildings appear taller than they are. And beyond ornamental advantages, a parapet roof can also increase curb appeal by hiding rooftop equipment like HVAC units.
Types of Parapet Roofs
Central to this project’s modern geometry are strong cantilevered roof forms, says architect Theodore Touloukian, who designed the Beacon Park—Lumen Restaurant in Detroit. Photo by Jason Keen
Parapet roofs are made up of parapet walls that encase the roof. Parapet walls are classified into four main groups: embattled, plain, perforated, and paneled parapet walls.
Embattled Parapet Walls
Embattled parapet walls are the parapet roofs of yore. This historical roof design is what may come to mind when you think of castles or forts. The alternating high and low ridges of the parapet were used as a defense strategy, from which people could both hide behind and shoot at an oncoming enemy or invader.
Plain Parapet Walls
Plain parapet walls are the most common type of parapet roof in modern building. Unlike embattled parapet walls, plain parapet walls are just vertical extensions of the wall at the edge of a roof. They are less decorative and largely incorporated into a building’s design for safety and privacy.
Perforated Parapet Walls
In contrast to the simple design of plain parapet walls, perforated parapet walls are, as the name implies, perforated with different-sized openings to create an ornamental design, such as a geometric or floral pattern.
Paneled Parapet Walls
Paneled parapet walls also provide ornamentation to a building facade. Sometimes referred to as “double walls,” paneled parapet walls are similar to plain parapets but include a decorative panel on the exterior wall. Paneled parapet roofs do not include any perforations.
Parapet Roof Shapes
Bellet’s work on the Meisel Gallery Building included repairs to the parapet roof. Photo courtesy of Bellet Construction
Parapet roofs are also characterized by the shape of their walls: flat, sloped, stepped, and curved.
Flat Parapet Walls
When you think of a parapet roof, you are most likely thinking of a flat parapet wall. With its straight-lined edge, flat parapet walls are the most common parapet roof shape and are used for buildings with flat roofs.
Sloped Parapet Walls
Sloped parapet walls are used on buildings with sloped roof designs, such as a gable roof. The sloped parapet follows the slope of the roof itself. A parapet roof with sloped walls is often purely aesthetic.
Stepped Parapet Walls
Stepped parapet walls are also largely used for sloped-roof structures. More common in older buildings, they follow the slope of the roof, but unlike sloped parapet walls’ smooth, straight edge, stepped parapet walls follow a staircase design.
Stepped parapet walls can also be used on flat roofs. In this case the parapet’s base remains flat with the surface of the roof, but the wall itself staircases up and builds to an apex.
Curved Parapet Walls
Curved parapet walls are similar to stepped parapet walls, with the key difference being that they have a curved edge instead of a staircase design. They can be used on both sloped and flat roofs.
Although this historical roofing design isn’t new, parapet roofs are still used today for both safety and aesthetics. And now that you know the benefits behind parapet roofs and the design versatility they bring to the table, it’s easy to see why.
