Weight: Because a clad over roof uses heavy timber, insulation materials and tiles, it can make it too weighty for some existing frames. You need something that’s far lighter. The lightest solid roof systems weigh around 31KG/M ².
Tip: Always ask your installer for the total unit weight of the new roof per Sq.M
Fire Safety: Another downside to a ‘clad-over’ system is that it doesn’t comply with current fire safety regulations due to not being effectively fire tested as a complete roof structure. As a result, it also won’t meet this part of building regulations. The structure of old conservatories can vary and only some individual components may have been tested. Solid roofs must be classified as AC, AB or AA in accordance with BS476-3.
Tip: Ask to see the fire safety certificate of the entire roof system before you commit to the project.
Building Regulations: It can be virtually impossible to obtain Building Regulations Approval for a clad over system because of their poor thermal value and structural integrity. This is a totally different thing to planning permission, something that’s generally not required. You will have to inform Building Control if you are proposing to modify a structure (including replacing a glass or polycarbonate conservatory roof with a solid roof). Once you have their approval, it confirms that the new roof is structurally sound.
Tip: Check that local Building Control has been informed before the conversion starts. Obtain a Building Regulations ‘Final’ Certificate and file it in a safe place.