As the owner of a commercial building, you’re likely to be asked to repair or replace your flat roof at some point. To make sure you’re not left with a mess of leaks and structural damage, it’s essential to understand how to install flat roof correctly.

The basic structure of a flat roof consists of a ceiling nailed to joists that support a deck, vapor barrier, insulation and a roof board. There are many different types of flat roofing materials available to choose from, with geography and budget often playing a role in which kind you select.

Step-by-Step: How to Install a Flat Roof

During the replacement process, the first step is to pull up the old roofing membrane, using specialized tools. Next, the crew lays down the underlayment, followed by asphalt shingles or rubber membrane sheets. A waterproof sealant is then applied to the surface, and flashing around protrusions such as vents and chimneys is installed.

The biggest disadvantage of a flat roof is the lack of drainage, which can cause water or snow to pool on the surface and lead to serious damage over time. To help prevent this, you should have your roof inspected regularly, particularly after storms. Also, you should regularly clean your flat roof of leaves, twigs and other debris that can clog drains. If you do this, your flat roof should be able to last ten or more years. The average lifespan of a flat roof is much shorter than that of a sloped one, however.