Building Renewal is an important part of our firm’s message on sustainability. A recent renewal project for an architecturally significant building demonstrated the challenges faced in achieving sustainability goals while respecting architectural legacy. Fortunately, challenges like these are a welcome form of motivation for our team to come up with innovative solutions.
The photograph above shows an “x-ray” image of the rebar in the floor slab, which is rendered in three colours of tape. The tape colours were coded to show rebar that was located near the top, middle, and bottom of the floor slab. In a building renewal project, it is important that understand where the structural “no-fly” zones are located. Creating this mock-up helped us determine where we can and cannot alter the structure. Though this is only a mock-up space, one could imagine this as a flooring pattern. The brilliant colours would suit a day-care and a subdued palette might work for an office.
Our team also proposed installing a Dynamic Buffer Zone (BBZ) on the interior of the existing envelope. The Dynamic Buffer Zone is an adaptation from technology developed for historically significant museum buildings to create a highly controlled (high humidity, stable temperature) indoor environment while allowing the building envelope to perform in its original historical manner. In the case of this renewal project, where significantly changing the exterior of the building was not an option, we are using this approach to buffer and control the building envelop, greatly enhancing its performance and creating a more stable and comfortable indoor environment. The benefits of a DBZ are further enhanced when paired with an integrated approach to developing a building’s HVAC systems. Essentially, the DBZ creates a ‘cushion’ of conditioned air (cooled in summer, heated in winter) around the perimeter of the building to absorb and address the heat gain and heat loss through the all glass facade.
The DBZ is achieved by constructing an interior wall of clear safety glass panels along the building perimeter. For this project, existing perimeter heating units were repurposed and combined with a flush floor grill, which allows return air to be drawn into the perimeter cavity, through a filter, and over a heating/cooling coil. The air is then drawn off the top by a return air duct, connected to the main air handling units serving the space.
The image above shows a mock-up on the Dynamic Buffer Zone (DBZ) on the top floor of this project. On the lower floors, the exterior envelope does not slope, and the DBZ will more closely resemble the diagram above. The size of the gap between the exterior curtain wall and the safety glass panels allows for maintenance and cleaning of the glass as well as space for mechanized shades.
This post was authored by John Potter.