The heat is on. No matter how you slice it, the climate is progressively getting warmer. But like the proverbial frog in a pot, slowly coming up to boil, most people seem oblivious.

If anyone really needed convincing, you could show them an endless stream of graphs and historic records (or comics that explain it better), showing the clear correlation between the astronomical rise of GHGs (greenhouse gases) and the global average temperature

But you can also give them another, more tangible and physical experience to hammer home just how much has changed in so little time; our historic buildings.

You see, the structures built using old techniques and materials were made for the English climate of the day; a climate colder than we have now, with fewer extremes. Of course, we always had storms, big freezes and hot summers – but the extremes were far less frequent.

Our historic buildings, and indeed many comparatively new builds, are ill-equipped for the oppressive heat and humidity we’re getting. And we are definitely going to get more of it. Domestic and commercial air conditioning isn’t widespread in the UK, because historically, we’ve never really needed it – and our heritage and historic properties aren’t readily adaptable to AC anyway.

Period properties were designed for a colder climate. The old roof structures of English towns were never designed to bake in equatorial heat – and this can often lead to overheating during heatwaves. 

The consequences of overheating in period properties are heavy, and can cause damage that only becomes apparent when the weather turns.

What does extreme heat do to old buildings?

Prolonged high temperatures can cause structural materials to expand and weaken. Roofs are especially vulnerable because heat accelerates the ageing process of tiles, slates, metals and wooden support structures. Tiles can become loose or crack. Wooden structures can warp or dry out.

And eventually, when the rain returns, the roof leaks. High winds can send loosened and cracked tiles flying. This kind of heat damage can take its toll on the structure as a whole, too – and it just gets worse when freezing temperatures hit during the winter…

Climate change is harming historic structures

Climate change poses an increasing risk to the period properties that were never designed to experience it. The combination of freeze-thaw cycles, excessive heat, heavy rainfall and stronger winds all contribute to this prolonged and gradual degradation.

It’s not just extreme heatwaves. It’s increasing UK storm activity and severity, shifting jet streams and a wider collapse of the once steady systems that govern the flow of air and moisture on our planet.

Roofs, the first line of defence on all modern and historic buildings, are damaged by constantly fluctuating temperatures. Extreme heat leads to material fatigue, and so does the cycle of freezing and thawing over winter. In wetter months, mould can set in – made all the worse by heat and cold; stretching, drying out and making porous materials even more prone to withholding moisture.

Higher rainfall and increased humidity accelerates rot and mould growth. This is bad news for heritage properties, because so many rely on wooden structures.

Without proactive maintenance, historic roofs could deteriorate beyond repair – leaving buildings exposed. Is there anything we can do to stop this?

How to protect historic buildings from extreme heat

Historic buildings go hard on insulation – which actually can help with keeping heat out – but they also need ventilation and airflow to regulate internal temperatures (and to prevent mould and damp). Historic building owners need to make sure that insulation and ventilation are up to standard.

And the roof needs to be regularly monitored for deterioration due to heat, not just during the summer. Often, the issues raised by heat only become noticeable during cold, wet and windy weather. 

As a somewhat extreme solution, the materials themselves can be swapped out for modern ones, made to look and feel traditional. Composite tiles or coloured concrete tiles, for instance – or artificial slates. Depending on the building’s listed status, this might be a challenge. But some companies still have new old stock, and some still manufacture tiles and roof coverings the old fashioned way.

If you need any help or support with historic building conservation, get in touch.

Historic building conservation since 1984

We’ve been preserving, restoring and caring for the nation’s most beautiful buildings since 1984. Get the advice and help you need about protecting your period property from extreme heat – from our team of historic building conservation experts.

To get a quote, contact us at [email protected].