"Summer is well and truly here and everyone is enjoying the long hot days and making the most of the sunshine while it’s here. But while you do, remember that just like the extreme cold weather we experienced only a few months ago, the recent heat wave brings its own implications for our buildings."

Summer is well and truly here and everyone is enjoying the long hot days and making the most of the sunshine while it’s here. But while you do, remember that just like the extreme cold weather we experienced only a few months ago, the recent heat wave brings its own implications for our buildings.

It’s not only people who can be burned by the sun, over a number of days in 2013 the reflected rays from the “Walkie talkie building” a (then) newly built glass clad sky scraper in London, actually melted the plastic trim and dashboard of several cars parked close by. The building was subsequently fitted with a permanent sunshade.

This may seem like an extreme example but fires started by the reflection of the sun’s rays, are more common than you might think. In March last year a woman in Lancashire walked in to find her curtains had been set alight by the concentrated rays reflected from her bedroom mirror. In a similar incident earlier this year, curtains were set alight in a care home near Cannock by a makeup mirror left near a window. There are many more reported incidents of this nature, so always be mindful of where mirrors are positioned in relation to windows, especially on days when the sun is particularly strong.

It’s not just the sun’s rays themselves that can cause problems for buildings and their occupants, but also the hot conditions created by them. When it gets too hot in the sun, we often retreat indoors to the shade, and many people’s work or education requires them to spend most of their day indoors. But for those of us without the luxury of air conditioning this can be almost as hot and even more stifling and humid.

The Health and Safety at Work Act 1974 states that “During working hours, the temperature in all workplaces inside buildings shall be reasonable.” But don’t leave work for the beach just yet, because “reasonable temperature” is subjective and depends on the type of workplace (a bakery or steel works is likely to be a high temperature environment most days). However, the HSE recommend that “If a significant number of employees are complaining about thermal discomfort, your employer should carry out a risk assessment, and act on the results of that assessment.” The same legislation also applies to schools and their pupils.

A major cause of heat building up in buildings is solar heat gain (A.K.A passive heat gain), this occurs when the sun’s rays pass through the glass of a window and are absorbed by materials within the building, these then heat up and radiate energy at a longer wavelength that’s unable to pass back through the glass, thus gradually increasing the temperature within the room. Modern windows are designed to take this into account, but a cheap easy solution for any susceptible existing windows you might have is to fit a preventative solar film.

Of course, it always helps to draw curtains and blinds before the sun has a chance to heat the room and if possible, open windows and doors at opposite ends of a room to allow a cross breeze of fresh air to pass through, taking the hot air out. Always remember which windows and doors you have left open and make sure they are secure before you leave the building.

The extremely hot weather we’ve had of late can take its toll on the fabric of a building too, causing cracks to appear and gaps to widen or close as materials shrink or expand in response to the heat; blistering can occur to flat roofs, caused by the heating of moisture between the roof layers; water may evaporate from traps, allowing bad smells to escape from drainage systems. It’s always important to be aware of any ongoing or developing problems with your building, and even more so during periods of extreme weather, even sunshine!

Of course we all want to enjoy the hot weather while we can, but sometimes the heat can be a struggle, especially when there’s no escape, here are 5 dos and 5 don’ts to help you stay cool indoors:

 Do try and maintain the temperature rather than reduce it dramatically.

  • Do open the windows to cause air changes.
  • Do use blinds and other window covers to stop the sun shining in before the sun hits.
  • Do use air-conditioning consistently where it is in place, remember to close doors and windows in these circumstances.
  • Do dress and drink appropriately, your body has lots of design features to keep you cool if you let it.
  • Don’t wedge fire doors open, only use the catches or mechanisms provided.
  • Don’t keep glass or reflective objects which could turn sunshine in to flame near to windows.
  • Don’t leave documents in the draughts of fans or open windows.
  • Don’t forget to leave the building secure at the end of the day.
  • Don’t moan about the UK weather it doesn’t help!!

Rob Finnen, Trainee Building Surveyor