Client
Mathew Hoy, Keefer Apartment Ltd.

Building Type
Heritage Building

Building Info
Two-Storey Wood-Framed

Service Performance Date
Ongoing

Challenge

The attic space of the building used to be occupied, and served as a conditioned space. As part of the in progress rehabilitation work, the Authority Having Jurisdiction had requested that the attic to be unoccupied, and turned into an unconditioned or indirectly-conditioned space.

As a result, the interior environmental condition of the attic has changed, imposing different environmental loads across the roof, walls and the floor of the attic. There were some uncertainties among various parties with respect to the applicable building envelope requirements for the attic assemblies.

How Did We Help?

Hamid Design Build was brought in to the project to review the attic, and provide engineering opinion with respect to the applicable level of building envelope control layers. In our approach, we made the distinction between new construction projects versus heritage buildings by emphasizing that:

• Imposing the building envelope requirements of new construction projects (specifically the thermal performance requirements) to heritage buildings may not necessarily be the most optimum and reliable approach. 
• Given that the assemblies in the heritage buildings are quite aged, and since they do not have the same level of moisture control layers as a new Code-compliant building, adding too much interior insulation in the assemblies, may potentially compromise the satisfactory moisture performance of the building envelope.
• The feasibility of applying the current Building Code energy requirements should be carefully assessed for each individual heritage building. 

With that in mind, our team took a holistic approach, and proposed two practical and reasonable options towards improving the moisture and thermal performance of the attic assemblies in response to the new environmental condition of the attic.