College of the Atlantic opens its second mass-timber building

Three years after constructing a 30,000-square-foot building from mass timber, College of the Atlantic in Bar Harbor has opened its second such structure, a 12,000-square-foot residence hall.

The 46-bed, eco-friendly building, called Collins House, was designed by OPAL Architecture of Belfast. The mass-timber structure was installed by an affiliated company, OPAL Build. Construction management was by AlliedCook of Scarborough. 

The structure uses blown-in wood fiber insulation from Maine company TimberHP, which sources small-diameter pulp trees and residual wood chips from the state and produces rigid insulation, batting and blown fill at the former paper mill in Madison.

With its mass-timber construction, wood infill walls and wood-fiber insulation, Collins House sequesters “biogenic” carbon and is expected to perform to Passive House energy standards.

“Biogenic” carbon is carbon dioxide that is absorbed by plants from the atmosphere during photosynthesis and then converted and stored as solid carbon making up the structure of the plant, Timothy Lock, a management partner at OPAL Architecture, told Mainebiz.

“If these plants can be harvested, replanted and then used in static things like wood in buildings, that extracted carbon dioxide is effectively negative global warming potential — the inverse of emitting carbon dioxide,” he said. 

Any plant-based material can do that. But the project prioritized wood for two reasons.

“It’s massive — I mean this literally,” Lock said. “Wood is a heavy material, capable of being used as building structure, even at large scale, and thus has much greater mass than other materials. If half of wood’s mass is that stored biogenic carbon, the more total wood mass one can get in the building, the greater that negative will be.”

It’s also a material that can be sourced locally, and is less intensive to harvest and extract than, say, concrete and steel, he said.

Last year, Lock was part of a team that provided guidance to the White House Climate Policy Office to set national standards for zero emissions buildings. The standards were released June 6. 

Collins Hall is one of a handful of buildings that already meets the definition of zero emissions, according to Lock. “This has become this petri dish in our office that allows us to test all the things that we know are possible,” he said.

The hall was dedicated to outgoing president Darron Collins and his family at an on-site ceremony June 9.