When used on roofs, expanded clay aggregate ensures that the necessary degree of insulation combined with high thermal inertia (the two indispensable requirements for comfortable winter and summer habitation) will be met. Due to its lightweight characteristics, it can be laid to a considerable thickness without excessively loading the structure.
In its loose form, after having been consolidated on its top surface, or after it being bound with cement, expanded clay can be used as an insulation layer incorporating falls for rainwater run-off, or as ballast on top of a waterproof layer. If it is to take an impermeable membrane, a screed will be required. It can also be applied on roof pitches if it consolidated with cement.
Expanded clay aggregate can also be used in roof voids as a durable insulating layer of high compressive strength that is impenetrable to rodents or birds. Its excellent thermal inertia makes it particularly effective to reduce summer overheating. If the roof void is not walkable, the product can be laid loose or placed in bags placed directly on the floor. If the roof void is to be accessible, the surface can be slurred or covered with wood-cement slabs; if it is to be walkable, the product can be mixed with cement and topped with a screed.