Most of the factors that cause the failure and affect the life expectancy of bitumen, polymeric and metal roofs can be identified before any problems occur. However, left unattended any one of them can ultimately cause the failure of the complete roof.  

Poor Design

Incorrect or lack of calculations for wind uplift and condensation risk analysis, are typical examples of design errors which can result in failure of the roofing system. 

Inadequate falls can cause ponding water, which may affect the laps and compromise the waterproofing integrity. 

Building movement may also require consideration, where applicable.

Incorrect Installation

Incorrect or lack of calculations for wind uplift and condensation risk analysis, are typical examples of design errors which can result in failure of the roofing system. Inadequate falls can cause ponding water, which may affect the laps and compromise the waterproofing integrity. Building movement may also require consideration, where applicable.

Material Properties

Bitumen based roofing systems rely on chippings, solar reflective paint or ballasting to provide resistance against UV degradation. Any loss or movement of this protection leaves the bitumen vulnerable to attack by Ultra Violet light, resulting in crazing, blisters, splits and ultimately water ingress. 

Metal roofs mainly rely on coatings to provide protection to the metal system. Damage or deterioration to the coating can lead to failure of the system. 

Any repair patches will also only provide limited resistance to water ingress.

Lack of Roof Maintenance

All roofs require maintenance, even if it is just to clear drainage outlets and gutters. If these are left blocked water can pond on a bitumen roof, leading to the potential for thermal shock of the waterproofing as the water freezes and thaws. Loss or movement of UV protection is also a maintenance item which if left unattended, can lead to serious or total failure of the bitumen roof system.