It’s hot today. Like, proper hot. Thirty-plus degrees hot. You’ve probably already seen a number of tweets of people’s car dashboards showing over thirty degrees on their thermometers. There will be moaning that it’s too hot, despite the fact we’ve begged for this weather all summer, and now it’s finally here.

Some of us, including myself, will actually enjoy this kind of weather. It’s what summer is supposed to be. However, our building materials, namely windows and doors in this scenario, aren’t used to this kind of heat. I’m thinking of PVCu materials, namely black doors, anything dark coloured in fact. It is not a day to be a black door!

Built for the climate

Our windows and doors are built for a fairly mediocre climate. Winter’s that aren’t all that cold. Summers that barely get above 20 degrees. In fact our whole year really is just an extension of Spring and Autumn, with the occasional fluctuation. That means our windows and doors are used to a consistent, reliably disappointing climate.

So when days like this come around, days where we get hints of a proper summer, things start to go a bit south. Especially for black doors or other darkly coloured doors.

I have a black door at home, technically it’s Schwarzbraun but lets not split hairs. It’s a fantastic door, fabricated by the good people at John Fredericks. However it is solidly south facing and gets a lot of sun when the weather permits. Naturally, it swells. Not too much, but enough so that it sticks when you open it and you have to give it some elbow grease to close it. It doesn’t last all day, and as the sun moves round and the temperature drops it cools back to it’s original size and works perfect again thereafter.

I know not to get the door seen to as it’s just a natural occurrence and to try and adjust the door whilst expanded may cause further problems when it cools down and is back at its normal size.

Fact of the matter is dark things soak up heat and expand accordingly. Even if they’re not dark, PVCu still has a tendency to expand anyway. Timber does the same, aluminium too but perhaps not as much as the others.

No service calls required

I don’t believe in going out to adjust too many of these doors. So often doors that have expanded due to heat are working perfectly fine. They are only sticking because of the sun and heat which they’re not normally used to. It’s sometimes possible to create problems by adjusting the doors whilst they are expanded, so when they cool and reduce back to normal size, an issue has been caused where it might not have been.

So I would say that service calls to doors that have expanded due to heat should be left to cool naturally. Plus, it would save the installer time and money in after-sales calls and I think it would provide a chance for companies to educate home owners on why their door is doing what it’s doing.

A problem never to be solved

Physics is physics, and it cannot be changed. When dark things are in the sun, they get hot and they expand. The same goes for dark doors of all materials. If they’re in the sun, they’re going to get hot and they’re going to expand.

I know companies are investing time and money into products like cool skins and heat reflection, but they only work to a certain degree. I can’t foresee any revolutionary product on the horizon which would negate the effects of 12 hours of hot sun on a black door.

But then, I don’t think there needs to be. When you look at homes in Spain, for example, there is a reason why a lot of their homes, and their windows and doors, are white. It gets extremely hot there a lot of the time. White homes, white doors and white windows mean the fabric of those buildings are kept as cool as possible. Now I’m not saying we need to start building white homes all of a sudden, but perhaps we should be using a dash of common sense when it comes to selling doors in south facing areas. To be aware that dark colours doors sold in sunny areas may well incur installers a service call or two over the course of the guarantee period.

Thankfully, this is Britain, and by Wednesday this heatwave is due to breakdown in the tried and trusted method of thunderstorms and torrential downpours. Which ironically would be good for heat expanded doors!

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