With some forecasters predicting one of the coldest and snowiest winters for almost 70 years, Tom Woodhouse, site services manager at Marley, gives his top tips for roofing in winter.
Predictions of extreme winter weather can’t be taken too lightly after the Beast from the East and Mini Beast in 2018, which, throughout February and March, saw the UK battered with three snowstorms in just a matter of weeks. As a result, construction activity ground to a halt, as sites were frozen with punishingly cold temperatures as low as -15°C.
Whilst the deluge of snow seen last year was rare, forecasters are predicting a very cold winter this year, with similar extreme weather events likely, so contractors should take steps now to make sure they are prepared for ongoing freezing conditions over the next few months.
As well as important safety precautions, there are other considerations to ensure the durability and security of pitched roofs in winter, such as choice of materials, storage and fixing. Here we give some of our top tips for roofing in the winter:
When it comes to working on roofs in winter, don’t take any risks.
Monitor the weather forecast so you can anticipate and be prepared for poor weather conditions. Carry out a risk assessment every day to check it is safe to work and conditions haven’t changed. Pay particular attention to working at height platforms and do not work on roofs in icy conditions. Always consider safety when working at height as scaffolding and roofs can become slippery.
Always install roofs to the BS 5534:2014 standard, as this was revised to help make roofs more secure against extreme weather.
Get a new fixing specification for each project, as this will help ensure the roof is as wind resistant as possible and help prevent call-backs. You can get a free fixing specification from our website www.marley.co.uk/specifying
Make sure that any clay tiles you use have passed all freeze/thaw test requirements.
In the UK, clay tiles face a challenging environment because they have to go through many more freeze thaw cycles than those used in colder or warmer countries. That’s why EN 1304: the European Standard details robust test criteria to confirm freeze/thaw resistance. Clay roof tiles in the UK have to pass a minimum of 100 cycles to achieve CE marked status when tested in accordance with the frost test method detailed in BS EN 539-2: the European Standard test method for frost resistance.
All of Marley’s clay tiles have been tested to meet these standards and carry the CE mark to demonstrate conformity. If you are using clay tiles manufactured outside of the UK, as a minimum they should match the standard BS EN 1304 when tested to BS EN 539-2, otherwise they may not be durable enough for our changeable weather conditions.
Ensure roofing products are stored correctly.
Many roofing products are delivered to site shrink wrapped but, for products that aren’t, like battens, make sure they are protected from the weather or store them in racks that have a roof. Battens should always be stored on bearers, spaced so that twisting and sagging is prevented and protected from water saturation.
Protect unfinished roofs.
Avoid using wet battens where possible and get roofs covered in at the earliest opportunity to prevent moisture damage.
Use dry fix where possible.
Mortar should be avoided in very cold conditions, so even though mortar bedding with mechanical fixings is allowed under BS 5534, it may be worth switching to full dry fix systems in the winter to enable roofing work to go ahead. Make sure any dry fix systems you use that require BS 8612 compliance, meet the requirements or have BBA certification.
If you are going to keep using mortar in the winter, the NHBC states that it should not be used below 2°C, to resist frost damage.
Seal underlay laps.
Always install membranes to BS 5534 requirements and seal the laps to prevent snow or water ingress.
Take steps to prevent condensation.
Avoid using a breathable membrane as the only source of ventilation and ensure there is supplementary high and low level ventilation.