What are parapet walls? A comprehensive guide to understanding
Parapet walls are the low-profile extensions above flat roofs that serve a critical role in waterproofing, design, and code compliance. But when poorly built or neglected, they’re also a top source of leaks and wall damage. This guide breaks down their purpose, common problems, and how to maintain or repair them.
Parapets are short walls above a rooftop. There are a few good reasons why parapets walls are used. The roof membrane generally is required to be installed up the parapet wall and often terminsted with a roof coping. There are a few good reasons why parapets walls are used.
1. Terminination of the roof membrane. A parapet allows the membrane to terminate under a coping which, in most cases, spans the top of the parapet wall and extends the each side of the parapet.
2. Flat visual wall line. Roof membranes are generally built so that they have a gradual or slight slope. That slight slope islope is generally more than 1/4 inch per linear foot. Over a large spin that gives the rooftop a slanted appearance. The appearance. The parapet though, on the other hand, can be built so that it is flat, and when you look at the building from the ground instead of seeing the roof itself, you see the exterior wall with a flat top.
Generally, people consider a flat wall to look better than a wall with a slightly slanted top.
A picture of a roof parapet, shown from the roof side, follows below.
Anyone can see the opposite side of that same parapet from the ground. Normally though, most people, who can only see it from the exterior side would think it just as the wall itself, not an actual parapet. From the roof though, you can see the wall just extends so many inches above the roof
In the picture below we show the same rooftop and parapet wall but at the rear termination. The rear termination of the roof is generally built with a drip edge fed into a gutter which channels water into a downspout and away from the building. This particular photo shows a building that is clad with cementitious siding. In this case the cementitious siding was installed thoroughly incorrectly by other contractors before our company was involved to make repairs.
Experiencing leaks or cracking in your parapet wall? We specialize in masonry and waterproofing repair throughout Washington, DC. Call (202) 800-1751 or contact us here.
Frequently Asked Questions About Parapet Walls
1. What is a parapet wall?
A parapet wall is a short vertical extension of a wall at the edge of a roof, terrace, or balcony. It serves both functional and aesthetic purposes, including safety, fire protection, and roof membrane termination.
2. Why are parapet walls used on flat roofs?
Parapet walls allow the roof membrane to terminate vertically and be protected under a coping. They also create a visually flat top line to the building, hiding the slope of the roof for a cleaner architectural appearance.
3. Do parapet walls cause roofing problems?
Yes, if not properly flashed or if coping is missing or deteriorated, parapet walls can cause water intrusion, leaks, and structural damage. Poor installation or incorrect siding can also lead to failure.
4. What is a coping on a parapet wall?
A coping is a cap installed on top of the parapet wall to cover and protect it from water intrusion. Copings often span both sides of the wall and are critical to keeping moisture out of the wall system.
5. Can you fix a leaking parapet wall?
Yes. Leaking parapet walls can be repaired by replacing or resealing coping, improving flashing, correcting drainage, and restoring damaged wall materials. A qualified contractor should assess the root cause before repairs begin.
6. What materials are used for parapet walls?
Parapet walls can be made from brick, block, stone, or framed with wood and finished with siding. They are typically capped with metal, stone, or precast concrete coping for protection.
7. Are parapet walls required by building code?
In many cases, yes—especially in urban areas or buildings with flat roofs. Building codes may require parapets for fire separation or fall protection, depending on roof height and local regulations.
If you’re experiencing leaks, flashing issues, or other problems with a parapet wall in Washington DC, contact Infinity Design Solutions at (202) 800-1751 for expert restoration and repair services.
