For people cooped up in offices during the summer, the idea of working outside when the mercury is rising sounds ideal. But actually, many roofers find that the heat can bring with it a number of difficult challenges. Jackie looks at how to weather the season and ensure that you – and your roof – won’t melt.
The summer is here, the sun is shining and office workers are stuck insidewith air-conditioning, sealed windows and a distinct smell of sweat in the air.
They may well be loosening their ties and wishing they were out in the fresh air but some jobs can be hard work during a heatwave – and roofing is one.
Health and safety
Togged up in heavy black work boots, a hard hat, long trousers and safety goggles, temperatures for a roofer mid-summer can reach a hideous 120C.
And that’s before they have begun laying the asphalt.
The Trades Union Congress (TUC) sees a dramatic rise in reports of fainting, dizziness and cramps from manual workers between May and September and warns that for some, the heat also places a dangerous burden on lungs and hearts.
Other common medical conditions associated with working in overheated workplaces include asthma, throat infections, and rhinitis.
The TUC has recommended maximum safe working temperatures of 27ºC for manual workers and 30ºC for sedentary workers but while office staff can open a window and pull the shades, controlling the environment for people working outdoors is more difficult.
The TUC suggests that such workers have regular breaks and drink a lot of water.
It also proposes that management arranges for workers to rotate to jobs in shaded areas whenever possible.
Employers should endeavor to send employees to work during cooler times of the day, provide more frequent breaks and introduce shading to rest areas. They should also provide free access to cool drinking water, encourage the removal of personal protective equipment when resting to help encourage heat loss and educate workers about recognising the early symptoms of heat stress.
Tips for personal protection:
– Wear high factor suncream. Too much sunlight is harmful to your skin and a tan is a sign that the skin has been damaged. Outdoor workers should take particular care if they have fair or freckled skin, fair hair or a large number of moles
– Keep your top on. This will help protect your skin. Choose light coloured, cotton fabric.
– Stay in the shade whenever possible, during your breaks and especially at lunchtime.
– Drink plenty of water to avoid dehydration.
– Check your skin regularly for any unusual moles or spots. See a doctor promptly if you find anything that is changing in shape, size or colour, itching or bleeding.
– Get wet. Roofers often use water to cool down roofing materials on site. If you have access to a water hose, consider wetting your face and hands regularly to bring your body temperature down.
How does the heat affect our homes?
When you consider how a building keeps cool, the most common thing that comes to mind is air conditioning.
But the first real line of defense against the heat is a building’s roof.
On a hot day, a good roof should release – not store and absorb – the sun’s rays.
So which materials work best?
Well traditional shingle roofing materials hold and transfer heat while roofing tiles made of felt-like materials overlaid with asphalt and tar will hold heat and even transfer it downward into a structure.
There are even more types of roofing available that will reflect light and heat upward and away from a building instead.
Here is a bit of information on some of the common roofing choices and how they fair when the weather gets hot:
Pros: Slate is durable and beautiful, with a natural colour range, and it lasts a long time with little maintenance.
Light colored and earth-toned slate help in reducing the heat absorbed by a building because it has natural reflective properties.
Cons: Some downsides to using slate are its high price and heavy weight.
Pros: There is a reason why these are so popular in places like Spain, Mexico and Italy when the heat gets really intense. They really survive the test of time and relentless baking in the sun.
Traditional terracotta tiles go through a baking process in ovens, or kilns, which makes them harder and less porous. Most often they’re molded into a half-barrel or “S” shape, forming interlocking arches across a roof. Space beneath the arch of each tile allows for air and water circulation and runoff, which prevents heat capture and keeps the home below cooler.
Cons: These materials are heavy and need solid foundations for load bearing. Another consideration with terracotta roofing is that cold and wet weather often make tiles snap. This is why they are a less popular choice in the UK.
Pros: Less expensive than slate and clay but more costly than traditional shingles. Concrete is heavy and takes a long time to heat, making it a good material for changeable climates.
Cons: Concrete is a heavy material.
Pros: Shingle roofs consist of overlapping panels made from a variety of materials such as fiberglass asphalt, wood, polymers, or metals. By far the greatest advantage of composition shingles roofing is its relatively low upfront cost. This is the most affordable roofing option in the short term, which is why so many homeowners favor it. Asphalt shingles will provide your home with a decent protection for at least 12 to 15 years for a very modest upfront cost.
Cons: Asphalt shingles are not resistant to extreme temperature variations, which causes expansion and contraction of the shingle and subsequent cracking.
Shingles perform better in cooler climates rather than hot temperature conditions and extreme heat causes shingles to crack and loose colour.
Pros: These are available with natural metallic finishes, oven-baked paint finishes, or granular coated surfaces.
Painting a metal roof can increase its solar reflectance and thermal emittance. Alternatively, you can apply cool reflective coatings.
Cons: Unpainted metals are typically good solar reflectors but poor thermal emitters, so they rarely satisfy low slope cool roof requirements.
Harnessing the power of the sun
Reflecting heat back up into the air is one thing, but holding the heat for use as alternative energy is quite another.
If you want to store up heat but not have it stored up in your home or office, a photovoltaic system – known as solar panels – is worth looking into.
These work by redirecting solar power and converting it into electricity.
Cost and location, however, are big factors. Start-up investment in products and installation is high. And you only see the benefits on sunny days.