What Causes a Flat Roof to Leak?

Many campus buildings feature flat roofing. Because there is no pitch, these systems rely heavily on a combination of product quality, membranes and initial installation. Some reasons your flat roofs may develop leaks include:

Clogged Drainage
A flat roof relies on a drainage system to remove rain water. If the drainage system is clogged, water will pond on your roof. Ponding water eventually leads to excess strain on the roof, and inevitably the water will start to seep inside.

Damage to the Perimeter Flashing
Flashing is installed on the edges of the rooftop as well as the interior parapets to protect the roof’s membrane. Moisture and water can seep underneath this flashing and into the building if it is not installed correctly, or becomes damaged.

Open Penetrations
Penetrations are common on rooftops, including as drains and pipes. When these are not installed properly, they leave a roof prone to leaks. They should be kept watertight with flashing, wraps, rain collars and pitch pans.

Damage to the Membrane
When a roof’s membrane becomes damaged, it allows water to enter through the opening. Membranes can become damaged for a variety of reasons. Sometimes it is just a matter of age.

The Age of Your Roof
Flat roofing in areas that experience hot summers or harsh winters will eventually start to fail due to age. Most systems deteriorate at about 15 to 20 years post-installation.

This article originally appeared in the issue of .

Featured

  • Armstrong World Industries Acquires Parallel Architectural Products

    Armstrong World Industries, provider of interior and exterior architectural applications, recently announced that it has acquired the Colorado-based Parallel Architectural Products, according to a news release.

  • Rhode Island Boarding School Completes Student Dorm Renovations

    St. George’s School in Middletown, R.I., recently announced the completion of a $26-million renovation project on Arden-Diman-Eccles Dormitory, according to a news release. The school partnered with Voith & Mactavish Architects (VMA) on the new space, which places a new focus on collaborative community spaces open to both boarding students and day students.

  • California K–12 District Finishes Renovations on Multi-Sport Stadium

    The Alameda Unified School District (AUSD) in Alameda, Calif., recently announced the completion of a renovation project on the Encinal Jr. & Sr. High School stadium, according to a news release. The district partnered with Quattrocchi Kwok Architects (QKA) and Bothman Construction on the facility, and funding came from Bond Measure B.

  • UNT Dallas Holds Ribbon-Cutting Ceremony for $100M STEM Building

    The University of North Texas at Dallas in Dallas, Texas, recently celebrated the opening of its new, $100-million STEM Building, according to local news. The ceremony on Dec. 2 preceded the first day of classes in the facility on Jan. 12, 2026.