Avoiding Wind Uplift on the Roof
Here in the UK, we’re all used to the changeable weather patterns that we see here. For those working in construction and roofing the weather is a particular consideration as rain can cause short term delays on roofing, as can ice and snow, both weather issues that are particularly prevalent at this time of the year. Wind can present a particular hazard for those working at height on roofs, so being aware of wind speeds and whether or not the conditions are safe to work in is essential. However, we don’t often consider the continuing effects of the elements once a roof is in place. Wind often proves to be most hazardous to the long-term integrity of a roof and there has been an increase in recent years in the number of wind uplift cases that represent a very real threat of serious injuries to members of the public and unnecessary damage to buildings.
The health and safety considerations to reduce the risk of wind uplift begin at the specification stage and, whatever fixing method is being used, there are risks associated with any system that has been designed and installed incorrectly which will be increased if a wind load calculation has not been done in an expert manner.
Any roofing system manufacturer should undertake wind load calculations which ensure that the whole system specified (including any existing systems that are being refurbished or repaired) is able to withstand the intensity of the wind pressure in that location. These calculations must be based on information relating to wind conditions in the project’s geographic location and should take into account the most severe wind speeds and gusts associated with the local area, rather than average wind conditions.
Coastal areas and other exposed locations often experience greater wind speeds and gust that may not be seen in other more sheltered sites close by. Wind load calculations should be tailored to the specific type of installation being used as an off the shelf approach is not acceptable. The calculation must be individually tailored to address factors such as the detailing involved, building height and location.
The manufacturer of a roofing system will have the technical expertise necessary to advise on the suitability of a specific system for the substrate being used in a specific installation and will advise on compatibility with recommended adhesives or mechanical fixings in order to provide effective wind uplift resistance.
During the installation process, the roofing contractor teams must ensure that the wind doesn’t lift the system as it is being laid and should avoid working at times when wind speed or gusts may present a hazard. Following installation, the integrity of the roof will depend on a number of factors, including the quality of the system used (including any mechanical fixings and adhesives) and the skill of the team carrying out the installation. Ensuring that there are no small areas where the wind may penetrate beneath the membrane and tear it from the roof is essential for the future integrity of the installation.