Hazard Knowledge

A fragile surface is a surface that would be liable to fail if any reasonably foreseeable loading were to be applied to it.

Personnel should be aware of the physical condition of the surfaces they are working on. Structures and buildings or elements of either, may be more fragile or weaker than they appear to be.

Some roof surfaces or elements of a roof structure can be fragile and often cannot support additional weight such as a person. This can lead to the surface giving way without warning, resulting in a person falling through the surface to a lower level or becoming trapped. The following are likely to be fragile:

• Fibre-cement sheets
• Rooflights
• Metal sheets, if corroded
• Glass
• Chipboard, or similar material if rotten
• Materials such as wood, wool, slabs, slates and tiles

Deterioration through exposure to weather and lack of maintenance can cause originally stable surfaces to become fragile, such as a metal sheet roof that has corroded overtime. In such circumstances it is safer to assume all surfaces are fragile.

Collapsed structures can present fragile surfaces due to a structural component being weakened through damaged and being incomplete. Refer to Unstable or collapsed structures.