Soaring “Freedom Mobile Arch” focuses on roof safety

Massive snow retention system installed.

Just weeks away from completion, the PNE Amphitheatre in Vancouver will feature one of the longest timber arch roofs in the world. Created of 60 interlaced timber arches that form into six remarkable barrel vaults, the massive 344-foot-wide starburst roof span will cover a 10,000-seat open-air entertainment facility. 

Designed by Revery Architecture, the $183 million project (officially called the Freedom Mobile Arch) is planned for year-round use. In Vancouver, where the average annual snowfall during the past 10 years has been 15.2 inches, the architectural firm specified a specialized snow retention system for the spectacular roof to assure the safe controlled evacuation of snow from its surface. 

Focus on snow retention

Snow retention was considered early in the development of the Freedom Mobile Arch. Everyone involved in the project, from the structural engineering team at Fast + Epp, to the code consultants at RWDI to the general contractors at EllisDon, were concerned with the issue. Working together, they consulted with the installation/execution team of Bothwell-Accurate, to find the best solution. Several meetings with Engineered Architecturals™ LTD and snow retention proposals using products from Rocky Mountain Snow Guards and S-5!® brought the resolution.

“We recommended a Single-Ply ColorGard® Bar-Style Snow Guard System that allowed the architects to achieve pattern designs with a distributed layout across the field of the roof for snow retention,” according to Nathan Morlock, president of Engineered Architecturals LTD. “These are sturdy metal pieces with a low profile that, when placed in a strategic pattern, can handle snow retention needs for this unique roof.”

Due to the massive size of the roof, Rocky Mountain Snow Guards provided 2,475 Single Ply Baseplates, 2,475 ColorGard® 2.0/X-Gard® Adapters and an expansive amount of aluminum tubing for the ferrules (used to create a pathway through the roof’s “build up materials” such as insulation, between the roof substructure and top membrane) to allow for fastening the baseplates. Engineered Architecturals obtained the extensive quantities of ColorGard Bars and VersaClips™ from S-5! to complete the system. According to Andrew Lewis, Project Manager at Bothwell-Accurate, the ColorGard Bars were painted in a Benjamin Moore® OC-56 color called Moonshine.

“The baseplate approach of attachment was critical given the roof build-up and scale,” notes Morlock. “That’s what made the system workable across the full assembly. There were varying depths of insulation over the back of the amphitheater, and a transition making installation at that location fairly complex.”

Starburst geometry to roof

Constructed primarily with Douglas Fir glulam and Spruce-Pine-Fir cross-laminated timber, the stunning roof on the Freedom Mobile Arch project was installed with acoustic and sound containment features. A rainwater collection system was also constructed into the roof and foundation to help provide landscaping and regulate runoff. 

"There are so many incredible features of this roof,” says Morlock. “Our company has dealt with the supply and coordination of snow retention products for many projects over the years. However, nothing beats this one. We’re pleased that we helped the designers achieve the aesthetic look they wanted for the roof with this specific snow retention product while providing a safe way for melting snows to gently slide off the Freedom Mobile Arch.”