Roof Ballast Rock

The ballast is used to keep the roofing system cool and of out of the sun s harmful rays thus keeping energy costs down.

Roof ballast rock.

Next the membrane is rolled over the insulation 2. A ballasted roof means that the roof membrane is not anchored or adhered in any way to the decking material. Single ply roofing materials aren t self adhered nor are they sealed together in any way. Over time the stones move around creating bald spots where the system isn t held down at all.

The stone ballast on a ballasted roof system is the only thing holding the roof system in place. It is however ballasted generally with gravel. There are no fasteners installed at all 3 and 4. Despite the positive qualities associated with a ballasted roof system there are some challenges.

The insulation is loose laid onto the decking. Stone ballast is no longer allowed by many building codes. The buildup is ballasted with a gravel layer of at least 50 mm and 80 kg m 2. Ballast stone can crush the underlying insulation creating weak spots in the roof membrane.

In windy areas ballast stone can actually blow off the roof creating projectiles below. Ballast is commonly used with roofs made of tar and gravel roof alternatives including ethylene propylene diene monomer epdm polyvinyl chloride pvc and thermoplastic polyolefin tpo single ply flat roofs. Gravel ballasted roofs with sikaplan or sarnafil single ply membranes are conventionally installed.