Working in ceiling cavities

15 December 2014
Working in ceiling cavities
The sun can cause the temperature in ceiling cavities to rise to temperatures which can be hazardous
to your health. Any work in a ceiling cavity needs to be monitored and controls put in place.
Working in ceiling cavities
Many existing houses in New Zealand have pitched roofs
which are relatively unshaded from the sun. These roofs
act as large solar collection areas that mean ceiling cavities
can reach temperatures which can be hazardous to health.
Working in high temperatures can put workers at risk from
the physical effects of heat, which left untreated, may
endanger life.
It is important to prepare for working in high heat.
Preparation includes planning the work so it occurs before
the temperature peaks each day and educating employees
about the dangers of a hot environment and the physical
effects of the heat.
Diagram showing typical heat gain in summer for an uninsulated home
Effects of Heat
The human body works best at a core temperature of about 37oC. Environmental heat will cause the
body’s core temperature to rise and the heart rate to increase. This
may lead to temporary or permanent changes in body functions which
is aggravated by physical activity.
When working in a hot environment, the body controls excess heat to
maintain a stable internal temperature. It does this by circulating
blood to the skin and through sweating. If a person is unable to control excess heat, this can lead to:
heat exhaustion, heat stroke, heat rash, cramps and fainting. These conditions are medical
How is the hazard managed?
In summer, the temperature will rise in the ceiling cavity and humidity may also increase. The lack of
air movement will make the area feel as if it is getting hotter, especially if the work is strenuous. Heat
can be managed using simple steps:
 Schedule work for cooler times of the day, i.e. early morning
 Dress for the working environment, wear loose-fitting, cotton hi-viz clothing
 Plan frequent breaks, rotate staff and jobs
 Drink water often during the work day – healthy guidelines indicate that men could drink 3+
litres total fluids per day and women, 2.2+ litres. However, when working in heat, increased
fluid intake is necessary
 Ventilate the work area if possible to lower the air temperature
 Look out for the symptoms of heat-related illness - monitor your own physical condition and that
of your co-workers
 Have an emergency plan in place
+64 3 341 9900 | [email protected]
Heat in ceiling cavities
The background reference material for this tool box talk can be found in the following documents:
WorkSafe NZ “what you need to know about temperature in places of work”. 1997.
Fletcher Building Tool box Talk – Heat Exhaustion and Heat Stroke”. November, 2014.
Drinking water:
Name three of the five effects of heat?
Heat exhaustion, heat stroke, heat rash, heat cramps, fainting
I have read / heard and understand the information in this Tool Box Talk, I will ask my Manager or an EQR staff f
member if I have any questions.
+64 3 341 9900 | [email protected]