Installing Roof Trusses - How Best to Avoid Damage and Undue Stress
Hoisting roof trusses with a crane is extremely common on job sites. Recently, Structural Truss Systems designed and built Western Canada’s first 120 ft long truss, and hoisting something of that size proved to be a challenge for the contractors! Luckily, they followed the same simple procedures outlined in this blog (and according to rules outlined by The Western Wood Truss Association, of which Structural Truss Systems is a member).
Following these steps ensured every single truss went up safely and without any damage.
Handling and Erecting Clear Span Roof Trusses over 60 Feet Long
For the 120 ft trusses, Southridge Construction managed the construction in Vauxhall, AB. The client required a storage building for potato equipment, and requested the large clear span ceiling.
Because of this immense size, the trusses were not raised in bundles, as is a common practice, but rather individually. This takes slightly longer, especially considering how many trusses were involved in this project, but it allowed for more accurate and safe installation procedures to be followed.
Installers should never hoist a truss by the peak. For trusses above 60′, a spreader bar two-thirds to three-quarters of the truss length, positioned at or above mid-height, is the best way to ensure a safe hoist that does not inflict any damage to the truss itself. This spreader bar should also be attached to the top chords and webs at 10′ intervals.
“Vertical strength on a truss is tremendous, but when you want to lift a 120 foot truss, you need a spreader bar otherwise it’ll bend like a noodle.”
Understanding Lift Points is Critical to Safe Installation
When hoisting trusses, it’s important to know where your lift points are. They are premitted anywhere along the chords – and by that, we mean anywhere other than the peak. This is the case for both truss bundles and individual trusses.
For this project, Southridge applied two lift points, though there was enough space in the span to have used three points as well. The Manitou crane was able to lift all 45 trusses into place within a two day period.
We were very pleased with Southridge Construction’s safe and efficient installation of our record-breaking 120 ft trusses! To view more of the hoisting and installation itself, please watch the video below.
