Building a roof on the ground

Posted on July 18, 2016 by Chris Magwood in Materials and techniques

At Endeavour, we tackle some fairly large building projects with our Sustainable New Construction program. This means completing a entire building from the ground up in just 5-6 months, from breaking ground to final finishes. Time is always at a premium, as is the safety of our students. For both these reasons, we often choose to build our roof structures on the ground and lift them into place with a crane.

: Large centre roof section, in 2014

: First of three roof sections in 2007

: Large main roof in 2009

: Complete house roof in 2010

: Complete arts centre roof in 2008

: Roof landing on frame walls, 2007

: Roof landing on round straw bale columns, 2008

: Roof landing on prefabricated straw bale house, 2010

: Roof with PV mounted landing on straw-cell office building, 2014

Building on the ground allows us to have a team working on the roof right from the beginning of the project, rather than only starting the roof once the foundation and walls are completed. This kind of “multi-tasking” shortens the entire build cycle, as the mostly-completed roof is set in place as soon as the walls are ready to receive it. The building receives immediate weather protection and the project moves into the finishing phases very quickly.

The process of building the roof is also appreciably faster when it’s done close to the ground. Much less time is spent going up and down ladders and scaffolding, and the accuracy of the work is improved because workers feel comfortable and safe and can take their time to do jobs properly.

And of course, doing the whole project at ground level is a much safer way to learn to how to measure, mark, layout and install all the components of a roof. Much of the work can be done with feet planted firmly on the ground, and even when working at the peak the heights are limited.

For our jumbo straw bale duplex this year, we are again employing this technique, and this time the process includes full construction of the soffits, fascia and gable end siding.

: Barn beams are carried into place

: Beams are placed on supports to mock the top of the walls

: Roof beams completed, awaiting trusses

: The first truss is carried into place

: First truss standing

: Second truss standing

: The first two trusses are carefully plumbed and fastened together to create a rigid unit

: First day of trusses done

: A fire-break truss between the units of the duplex

: The heavy sheathed fire truss takes many hands, and is much easier from the ground!

: All the trusses are up and braced

: The exposed rafter tails are treated with non-toxic Lifetime wood preservative

: Painting the wood for soffits with Lifetime

: Soffit boards are installed on top side of trusses

: Hip soffits require careful measurement

: A sneak peak at the exposed rafter tails and soffits

: Gable end soffits are installed

: Gable end is strapped for the application of cedar shingles

The more complex the roof and roof details, the more sense it makes to build this way. None of our roof lifts have required more than 4-8 hours of crane time, which makes it a very affordable process (ranging between $750-1200), especially considering the time savings during construction.

And the day of the lift is exciting, a bit nervous, and a great sense of accomplishment as the building goes from open walls to full enclosed structure.