In the latest of our series on technical troubleshooting, Mat Woodyatt, technical training manager of BMI UK & Ireland, looks at the causes of, and problems arising from, hip end failure.
The failure of a traditional mortar-bedded hip end detail, is an all too common sight. This hip may have been installed to what was an acceptable standard, and the hip end tile was supported by a hip iron in accordance with best practice.
Nevertheless: the detail has failed and the hip tile has become dislodged from the roof closely followed by the adjacent hip tiles. And, as a result, the loss of hip tiles will start to allow water ingress into the roof space and subsequent problems.
The 2014 updates to code of practice BS 5534: 2014 +A2: 2018 Slating and Tiling for Pitched Roofs and Vertical Cladding introduced recommendations to address the reliability issues with traditional mortar-bedded ridges and hips. It says that all mortar-bedded ridge and hip tiles should either be accompanied by a mechanical fixing or replaced entirely by a dry fix solution.
With an appropriate mechanical fix, the hip end tile would still be in place, although cracked mortar could still fall out if in poor condition. The loss of the material is a prime concern here as it not only a question of roof performance, but also one of safety. The risk is not only of tiles, but also sections of heavy mortar crashing to the ground beneath which would easily cause injury – and possibly a fatal one at that.
Dry fix takes the installation a step further. Some people are not that keen on the aesthetic of dry fix, yet it’s nothing to the poor appearance – and poor performance – of crumbling, degraded mortar. In addition to keeping the property’s occupants and passers-by safe, dry fix is quick and easy to repair and maintains a clean aesthetic and professional finish to the detail.
BMI UK & Ireland offers a range of pitched and flat training courses on all aspects of roof design, estimating and installation.