Roof common problems: Flat roof seams

A few days ago, I got a call from a business in Doral FL. “General, my roof is leaking consistently from the back porch”. Like most pack porch roofs in Florida, the roof was a flat. Flat roofs are defined in the industry by their low slope.

As I made my way to the roof and started doing my roof forensics, I noticed very quickly the problem. The laps were not properly adhered. As the joints between the rolls (laps) were separated, every time there was heavy rain with wind, the customer would experience leaks.

In commercial or residential roofing, most flat roofs are manufactured in rolls. These rolls average between 6’ and 8’ wide. Since most flat roofs are larger than 8’, most of times, several rolls must be layed together and seamed. These seams are the most vulnerable spots in Flat Roofs.

Seaming laps properly is the roofer’s job. Many different conditions need to be considered for a properly seamed lap. In this specific case, the previous installer simply did not use compatible materials to ensure long-term adhesion.

The solution here was to remove the entire roof and install a new one. The water infiltration not only damaged the interior, but the wood deck as well.