Weight: The heaviness of a clad over solution will often be no good for any existing framework due to it having weight timber, insulation materials and tiles. Any new system must be lightweight, with the lightest solid roofs usually weighing around 31KG/M ².
Tip: Always ask your installer for the total unit weight of the new roof per Sq.M
Fire Safety: In any case, ‘clad-over’ systems are not compliant with current fire safety regulations as they are not sufficiently fire tested as a total roof structure, which is essential to satisfy the relevant part of building regulations. There are so many variations between roofing structures, and it may well be that only certain components have been tested. Solid roofs must be classified as AC, AB, or AA in accordance with BS476-3.
Tip: Don’t agree to the project until you have been given sight of the fire safety certificate for the entire roof system.
Building Regulations: It’s rare for a clad over system to receive Building Regulations Approval because of its low thermal value and poor structural integrity. Planning permission is something complete separate to Building Regulations Approval and will likely not be necessary. Building Control will need to be notified when modifying a structure, such as fitting it with a solid roof, so they can decree if the new roof is structurally sound enough and officially confirm it.
Tip: No conversion should begin before local Building Control has been told. The Building Regulations ‘Final’ Certificate should be stored away safely.