Why Do Commercial Roofs Have Small Rocks on Them?

While it may not be common for most people to walk across a flat commercial roof, those who have done so may notice something unusual: a layer of small rocks covering the surface. These tiny rocks aren’t just for decoration, they serve an important purpose in protecting your roof from damage and the elements.

The small rocks on your roof, often referred to as roof ballast or gravel, are part of a roofing system in which materials like EPDM (rubber membrane) or built-up roofing (BUR) are weighed down with gravel or pavers instead of being fully adhered or mechanically fastened. Their primary role is to hold the roofing materials in place.

Hot, sunny days (especially in the intense Texas heat) can cause roofing membranes to deteriorate more quickly. In these conditions, the gravel acts as a shield, absorbing and reflecting UV radiation to extend the lifespan of the underlying materials.

During the summer, gravel also helps reduce heat absorption, maintaining more comfortable temperatures inside the building. Conversely, it provides an extra layer of insulation during winter, helping to keep the interior warmer on the coldest days.

Many areas in Texas are prone to high winds, tornadoes, and storms. In such situations, the ballast layer helps weigh down the roofing system, reducing the chance that wind will lift or tear off membrane materials.

Gravel also serves as a safety feature, creating a protective barrier against fire, foot traffic, dropped tools, and other mechanical damage.

That said, it’s important to note that not all types of rock offer the same benefits, and ballasted roofing systems may not be ideal for every commercial or industrial building.

For years, Elevation Roofing & Restoration has proudly helped Texas businesses and property owners protect their buildings from the elements. Whether it’s a commercial or residential project, our team of professionals is here to guide you in every step of the way, from inspection and planning to expert installation and ongoing maintenance.