Flat roof insulation boards - held in place by precast concrete ballast elements pref. lettered or shaped to discourage removal

摘要

The insulation (2) for a flat roof (1) comprises a layer of insulation boards held in position by pre-fabricated concrete ballasting elements (4). Each element is pref. provided with a cast-in test warning that removal is prohibited and may be formed without parallel upright faces e.g. may have a trapezium cross-section or a triangular cross-section with acute apex.