Ballasted Roof Systems

A single piece of gravel doesn’t hold much weight. Piles and piles of gravel, on the other hand . . . Well, they can give protection to an entire roof. Ballasted roof systems use gravel or pavers to weigh down the roof’s membrane and other structural components. They’re a very popular type of commercial roofing system because of their functionality, aesthetics, affordability, and ease of installation. If you’re interested in learning more about the history and composition of ballasted roof systems, stick around. We’ll also be delving into the pros and cons to help you decide if a ballasted roof is right for your building.

Ballasted Roof Systems

Ballasted Roof Systems

HISTORY

Ballasted roof systems are around 40-45 years old, as they began appearing sometime in the early 1970s. They utilize a thin layer of gravel (with rocks about an inch in diameter) to hold  the components of the roof in place. In the 1980s, pavers were integrated into ballasted roof systems to create paths and walkways, and in the 1990s, some contractors shifted from stone to soil, so that they could create green roofs with vegetation. The numerous benefits of the ballast method have helped it remain popular over the last four decades.

COMPOSITION

Although soil and plant life can also be used, most ballasted roof systems use gravel or pavers to hold down the roofing components. Depending on the material and thickness, the weight can vary between 10 and 25 pounds per square foot. The contractor loose-lays all of the components (the thermal barrier, insulation, an EPDM membrane, etc.), so none of the items are fastened to each other or the roof deck. Membrane seams are sealed and the waterproof layer is secured to the parapet, but that is all. The weight of the ballast layer holds it all together.

PROS & CONS

Because ballasted roof systems eliminate the need for adhesives and fasteners, they are affordable and can be quickly installed. Aesthetically, they look very natural and complement many architectural styles. Plus, if you add pavers, the roof can become a relaxing outdoor space with walkways or a plaza. Ballasted roof systems are also virtually fireproof, very long-lasting, accommodating to building movement, and durable. Because they are so flexible and loosely-laid, they can be easy to repair. Finally, if you’re concerned about your roof’s environmental-friendliness, you’ll be pleased to know that the membrane is fully recyclable and (if the gravel is stacked to 24-25 pounds per square foot) the roof’s thermal mass and reflectivity can reduce your energy use.

On the other hand, if many problems do arise, ballasted roofing systems can be frustrating to fix. They’re very heavy and make it difficult to locate problem areas. Plus, if you live in an extremely windy area, you may have issues with the roof shifting out of place. Finally, the ballast layer can collect dirt, oil, chemicals, and other pollutants over time, which can damage the membrane.

Ballasted Roof Systems

Looking to replace or repair your commercial roof with a ballast system? If you’re interested in learning more about ballasted roof systems and you live in the Springfield, Missouri area, give Adam Cowherd Construction a call at 417-877-7548 or click here to get a free quote. It’s that easy!