Building a roof can be intimidating, and statistically the most dangerous element of making a building. The heights involved add risk, time and a lot of effort.

Whenever we have the opportunity, we build our roof structures – including all sheathing and as much finishing as possible – on the ground, and then use a crane to lift the roof and place it on the building. In this way, we reduce the risks associated with working at heights, lower the amount of physical labour involved in carrying materials to roof height and bring protection to our building faster.

For the teachers’ union office, we once again had enough room on the building site to do just this. We set up two rows of beams on the ground at the back of the property and fully erected the entire roof, including trusses, bracing, strapping, membrane, steel sheathing, light tubes and the full PV array. All of this was accomplished with the fascia less than two feet from the ground!

As we’ve found to be typical, the craning is a relatively quick process. We were slowed somewhat this year by wet conditions on site that made placing the crane in the right position difficult, but we still put all three sections of the roof on the building in a single day.

A quick look at the math makes a pretty good financial case for building roofs in this way. The cost of a day’s rental of a crane and operator is easily paid back by the efficiency and reduced labour time of building on the ground.

It’s not a carbon free practice, but when the site and conditions are appropriate – and particularly when working with student builders – it’s one place that we’re willing to let fossil fuels and mechanical advantage help us out!