Hot Weather Survival Guide for Construction Workers

August 2, 2018

The dog days of summer are upon us, and outdoor workers need to take extra special care to protect themselves from the heat. We recently published a post about heat and sun safety for event organizers and staff. We’ve built upon that post to include relevant hot weather safety tips for construction site workers, who face their own unique set of challenges when it comes to preventing heat stress.

For outdoor workers, direct sunlight is usually the main source of heat. Humidity also contributes to the problem. Heat can be dangerous because it puts extra stress on your body’s natural cooling systems. When heat is combined with other stresses – such as hard physical work, loss of fluids, fatigue or certain pre-existing medical conditions – it can lead to heat-related illness, disability, and even death. This is why summer weather conditions can be especially hazardous for those who perform physical labour outdoors.

The reality is that heat stress can happen to anybody – even those of us who are young and relatively fit. It’s important to know the causes and symptoms of heat-related illness, as well as ways to prevent heat stress.

Heat stress prevention can be broken down into three main components: acclimatization, controls, and protective clothing.


Generally speaking, the longer you work in a hot environment, the better your body acclimatizes to the heat. Consider organizing your employees’ work to allow for acclimatization.

To help your employees (and yourself) become acclimatized to the hot weather, try practicing one of the following progressive approaches:

  • For experienced employees, try limiting your shift time in hot working conditions to 50 per cent on the first day, 60 per cent on the second day, and 80 per cent on the third day. You should be able to work a full shift on the fourth day.
  • For new or inexperienced employees, you should start off spending only 20 per cent of your shift time in hot working conditions on the first day. You would then increase your time by 20 per cent on each subsequent day. You should be able to work a full shift in hot working conditions the fifth day.
  • Alternatively, instead of progressively increasing the time during which you are exposed to the heat, you can become acclimatized by gradually increasing the physical demands of your job over a week or two.


When outdoor conditions create the potential for heat stress, control measures must be taken to limit heat and sun exposure. These include engineering controls and administrative controls. Your selection of appropriate workplace controls will depend on a number of factors, such as available resources and the type of work being performed. We’ve rounded up some measures related to hot weather that would best apply to a construction site worker:

Engineering Controls

Most engineering controls require some investment in permanent solutions. Examples include installing air conditioning in work spaces and shielding sources of radiant heat. Given the temporary nature of most work sites, there may not be many opportunities to implement engineering controls.

However, one thing you can do is try to keep work areas cool by providing some shading. As well, consider providing personal fans to your employees. Fans increase air speed and movement, and reduce humidity – helping to improve sweat evaporation and thereby keeping you cool.

Administrative and Work Controls

Supervisors on site should assess the demands of all jobs and have monitoring and control strategies in place for hot days. For instance, they should plan to increase the frequency and length of rest breaks for their employees. Try scheduling regular breaks and encouraging your employees to take them in a shaded or air conditioned area. If there is no air conditioned rest area on site, then an air conditioned truck works just as well.

Try to schedule the most labour-intensive tasks for cooler times of the day, such as the early morning or evening. If possible, assign additional workers to help distribute the work, or slow down the pace of work altogether. Remember: heat can become deadly when combined with intense physical labour and fatigue.

Finally, hydration is critical to combat the negative effects of heat. Make sure your workers have access to cool (10 – 15 degrees) drinking water, and remind them to drink a cup about every 15 to 20 minutes – even if they’re not thirsty. They may need to consume as much as one litre of water each hour to replace fluid loss. Try to discourage workers from consuming excessive amounts of caffeine, as it dehydrates the body. This may be difficult to do, but they will thank you in the long run!

Protective Clothing

The last piece of the puzzle is protective clothing. The right clothing can make a big difference when it comes to heat and sun safety, as well as personal comfort. For starters, wear light, loose clothing (if permitted) that stops radiant heat but allows sweat evaporation for efficient body cooling. While it seems counterintuitive, wearing clothing that covers as much skin as possible is best to protect from sun exposure. Tightly woven fabrics offer more sun protection than loosely knit ones, but you may need to find apparel that strikes a balance between UV protection and breathability to ensure your comfort.

Construction site workers face the added challenge of having to follow safety regulations when it comes to their apparel. You are probably required to wear hi-visibility clothing and personal protective equipment (PPE). You are also probably prohibited from wearing shorts on site. Thankfully, hi-visibility apparel is available in breathable, moisture-wicking styles. Many of our Fence Guys love the Coolworks ventilated work pants, which offer the comfort of shorts without violating site safety regulations.

Finally, though it isn’t clothing, it’s worth mentioning sunscreen as a protective measure. Encourage your employees to apply sunscreen, and remind them to reapply it regularly if they are sweating. You might even consider providing sunscreen to your staff. At Modu-Loc, sunscreen is something we make available to our field employees. Look for a broad-spectrum sunscreen with a sun protection factor (SPF) of at least 30.

Training and Information

One of the most important things you can do is train your workers to recognize the signs and symptoms of heat stress. Educate your employees about the factors which may increase the risk of developing a heat-related illness, and teach them how to respond to heat stress. Distribute information about the dangers of hot weather and post it in prominent areas on the construction site. The Canadian Centre for Occupational Health and Safety (CCOHS) has some great resources available, including this publication and these posters.

Consider starting a “buddy system”. Since people are not likely to notice their own symptoms, it’s helpful to have someone else looking out for the signs of heat-related illness. Have a plan in place for heat-related emergencies, and make emergency contact information available.

Hot weather can be dangerous, especially for those in construction who work outdoors for extended periods of time. By taking the proper precautions and having the necessary controls in place, you can help mitigate the factors that contribute to heat stress, and reduce the risk of heat-related illness.

For a list of heat-related illnesses, their symptoms, and treatments, please see this CCOHS fact sheet.

Author: Joanna Bieda

Joanna Bieda is the Director of Marketing and Communications at Modu-Loc Fence Rentals, and has been with the company since 2014. She loves writing and is a self-professed data nerd. She thoroughly enjoys teaching customers about all things fence via Modu-Loc's blog.

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