Each year as many as 200,000 buildings in the UK are damaged by gales. Roof damage represents by far the largest sector of the total number of building elements affected. Roof tiles and slates tend to vary according to how they are fixed. Concrete & Clay Plain tiles are defined as a ‘Double-Lap’ roof covering and, as a minimum (as stated in BS5534), Double-Lap roof coverings require every tile in every 5th course to be twice mechanically fixed. A fixing specification will determine if a more regular fixing schedule is required, i.e. every tile in every 3rd course to be twice mechanically fixed.
Concrete interlocking tiles are classed as a ‘Single-Lap’ roof covering. BS5534 requires that all Single-Lap roof coverings are at least once mechanically fixed. A fixing specification will determine whether the mechanical fixing that is required is a nail, a clip or nail and clip.
The above are MINIMUM requirements and will always be superseded by the generation of a Fixing Specification, which is site specific and takes into account factors such as:
• Environment – Average wind speeds and loadings
• Location – How exposed is the roof? Local topography
• Roof design – Is the roof a steep or shallow pitch?
• Building height – Is the roof level high?
• Product choice – Weight of product, leading edge?
Any fixing specification carried out using the Marley Fixing Specification tool will be calculated in line with BS5534. This calculation assesses the wind load on each tile or slate as a uniformly distributed load and also takes into account the porosity of the tiles or slates and the effectiveness of the substrate.
Access our fixing specification tool here.