While there are some advantages to having a flat roof, they are generally more vulnerable to problems caused by bad weather – in dry climates these problems aren’t as severe, but in the UK we rarely have the luxury of extended periods of warm and dry weather. As we are getting into the winter months, it’s time to consider the impact of wet and cold weather on your flat roofing system.

Bowing in the Roof

Without a direction to run off in it’s possible that snow, hail, or even heavy rain can collect on a flat roof and put unnecessary down-bearing pressure onto the structure. Snowfall is really the biggest danger here – its texture and the slow, steady speed it tends to fall mean that it can settle on roofs in very large quantities. Unlike hail it’s unlikely to bounce off, and unlike raindrops it won’t run off a flat surface once a large quantity is collected.

If the weight causes the roof to bow in shape, then when the snow melts – or when it later rains – a puddle can collect on the roof. Unless a roof-pond is something that you like the sound of, this is undesirable as it will of course further increase the dip in shape, but the prolonged presence of water can have other implications too:

Freeze-Thaw

They key to understanding the effects of freeze-thaw is knowing that when water freezes, it expands. In countries with very hot days and very cold nights the water in rocks and bricks freezes overnight, expanding any cracks or holes by putting pressure on them from the inside. This effect is most obvious in the dramatic cracks and layers found in some desert rocks.

When water makes its way into the cracks in your roof in the UK, the result will be a lot less pronounced but will still damage the integrity of the roof. In winter, the temperature often hovers at around 0°C, and we often have overnight frosts that then melt in the early mornings. Any small weaknesses will be widened and worsened by this freeze-thaw action. The best way to prevent this is with a pitched roof that will allow rainwater to run off, preventing it from freezing and refreezing. Even very low pitch roof tiles, from 10°, can greatly reduce the effects of frost damage. There isn’t much you can do to prevent dew drops from forming into a light frost cover, but these will be less damaging than a heavy covering of rain or snow.

Leaks

The bows in the roof caused over time will increase the risk of a leak, as rain will simply collect. Any faults in the roof are much more likely to give way under the weight and let water inside if the water is unable to run off. This can cause hygiene and structural problems by leaking into your building’s structure and having serious repercussions all the way through.

This damage may not be immediately obvious to you, and by the time you realise what’s happening it could be very advanced and expensive to fix. Mould and mildew can cause serious health problems, as well as ruining furniture and paintwork. Meanwhile the increased moisture can also cause damage to your decoration and any metal or wooden fixings or features.

Flat-to-pitch roof conversions are highly recommended for any home or business owner with a flat roof. The investment in protecting your property will save you a lot of heartache in the long run, as the problems that can be caused over time can be avoided altogether with some preventative action. If you’d like to see how we can help you protect your property, contact us for a no-obligation discussion.