A new player is gaining prominence on construction projects across the country; the Building Envelope Specialist (BES). Their increasing impact on designers, contractors, owners and developers is very much a function of a regulatory environment that sees Canada moving towards higher levels of energy-efficiency and durability by 2030.
“Building envelope” is a term that describes all outer elements of a structure —walls, windows, roof, and foundation. The design and integration of these elements play a key role in determining the level of occupancy comfort, how much energy will be required for heating and cooling, and the life expectancy of the structure itself.
What does a BES do? They develop assessment reports that evaluate a building envelope’s condition and performance. While this can be conducted on an existing building at low initial cost, assessments are now more commonly based on advanced computer modelling when the building is still in the design stage.
There is a comprehensive menu of components to be considered: water and vapour control, air control, thermal control, fire safety, acoustics, day-lighting, system maintainability, and durability. Not all carry equal weight in any given project — they can vary in importance depending on the building’s setting, location and climate.
The degree to which the BES and their assessments relate to projects is also driven largely by clients, says Ben Bondzio, of Entuitive Corporation. “There are varying degrees of literacy. Institutional clients, such as governments, universities and colleges, seem to be more understanding and accepting of the science and the extra services a BES offers,” he says. “They recognise that they are front-loading the cost of long-lasting performance for an asset that they are going to own for its entire life.”
Bondzio says that in contrast, the objective of most commercial developments today is getting a building completed and occupied as quickly as possible. “There are different degrees of reticence,” he says, when describing the BES’ role. “Sometimes it’s just a matter of code consulting — meeting the requirements of the code and then moving on.”
Historically, building envelope analyses have been performed by the architect alone or perhaps through a BES working quietly alongside the architect in the shadows. However, Bondzio says this is changing in the face of energy efficiency and durability expectations. It’s bringing the BES to the table early on as a specialist.
It’s due also to the increased use of BIM technology by designers and builders. “BIM is allowing a more integrated design process earlier in the project,” says Tristan Truyens, a Building Performance Analysis lead with Entuitive. “Certainly, in terms of the full energy building performance world, the integration between BIM and energy analysis platforms allows us to get quite detailed quite quickly about the performance of individual envelope systems and how they will impact the building performance. In contrast, the tools we were working with 10 years ago really only enabled us to provide some very broad stroke moves.”
Because the BES’s work includes exterior elements of a building, it creates an interesting creative dynamic with designers and architects. “I’d like to say that we enable them to maintain architectural design freedom in the face of an increasingly stringent code landscape,” says Truyens. “So much of the architect’s vision is the aesthetic. This is particularly true with cladding and glazing — that’s what people see from the street. We try to work with the initial vision. Typically, with different cladding systems, we can look at how they are backed up and insulated and maintain the aesthetic vision that way.”
“It’s a world of converging carrots and sticks right now,” says Truyens. “There are aspirational NetZero building tools out there for those who want to win awards. However, pretty much all building codes are on a trajectory to get to a NetZero energy operation by 2030. So, you’re going to get there one way or another. However, those levels of performance don’t come from rules of thumb. That’s where Building Envelope Specialists come in.”
John Bleasby is a Coldwater, Ont. based freelance writer. Send comments and Inside Innovation column ideas to email@example.com.