Weight: The main issue with a clad over solution is that they can be too heavy for some existing frames due to them using heavy timber, insulation materials and tiles. Any new roof needs to be lightweight and the lightest of them weighs around 31KG/M ².
Tip: Always ask your installer for the unit weight of the new roof per Sq.M
Fire Safety: A ‘clad-over’ system also fails to satisfy existing safety regulations as it isn’t effectively fire tested as a complete roof structure, something that’s essential to meet building regulations. The original structure can vary between jobs, which means that only individual components may have been tested. Solid roofs must be classified as AC, AB or AA in accordance with BS476-3.
Tip: Before the project begins, ask to see the fire safety certificate for the entire roof system.
Building Regulations: You will find it difficult getting Building Regulations Approval for a clad over system as it has a low thermal value and structural integrity. Please, don’t mistake planning permission for Building Regulations Approval – they’re not the same thing. Building Control must be notified when proposed changes will be made to a structure as the new roof has to be structurally sound.
Tip: Building Control must be informed before any conversion begins. Obtain a Building Regulations ‘Final’ Certificate and keep it in a safe place.