In roofing terminology, what does ballast refer to?

Ballast in roofing terminology specifically refers to a weight used to anchor roofing materials, particularly in membrane roofing systems. It serves as a stabilizing weight to hold down the roofing membrane against wind uplift and other environmental forces. Ballasted roofs often utilize large stones or concrete pavers placed on top of the membrane to ensure it remains securely in place without the need for adhesives or mechanical fasteners. This method can enhance the durability and longevity of the roofing system while also providing insulation. Understanding the role of ballast is crucial for maintaining the integrity of certain roofing installations, especially in climates prone to high winds or severe weather conditions.