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

  • Houston K–12 District Opens New Elementary School

    The Lamar Consolidated Independent School District (Lamar CISD) recently announced the completion of a new elementary school in a western suburb of Houston, Texas, according to a news release. Haygood Elementary School measures in at 110,000 square feet, has the capacity for 854 students, and is the first of three new schools scheduled to be built in the Cross Creek West community.

  • Wisconsin District Breaks Ground on New Elementary School

    The School District of La Crosse in La Crosse, Wis., recently broke ground on a new elementary school that will consolidate the students and staff of two existing schools, according to local news. Funding for the school comes from a $53-million referendum approved in 2024.

  • Hawaii Elementary School Breaks Ground on New Classroom Building

    Kealakehe Elementary School in Kailua, Hawaii, recently began construction on a new, $16-million classroom building for its campus, according to a news release. The 13,000-square-foot building will stand two stories and connect the existing upper and lower campuses.

  • DFW-Area District Opens New Replacement Middle School

    The Eagle Mountain-Saginaw Independent School District near Fort Worth, Texas, recently held a ribbon-cutting ceremony for a new replacement middle school campus, according to a news release. The new facility for Wayside Middle School, originally established in 1964, was built on the site of the former district administration building and funded through Bond Proposition A in 2023.