Engineered Slab Design for Detached Garage, Pickering
This project involved the structural design of a detached garage featuring a second-storey storage loft.
Parsways was retained to provide OBC Part 4 engineering services, supporting the architectural BCIN designer in realizing a structure that exceeded standard prescriptive code limits.
Location: Pickering, Ontario
Completion: 2025
Sector: Residential – Accessory Structure
1. The Challenge
While the project footprint was typical for a garage, the structural requirements were not. The design called for a steel superstructure (W-beams and HSS posts) to support significant storage loads in the loft. This created two primary technical constraints:
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Structural Loading:
The steel columns imposed concentrated point loads that a standard residential slab could not support.
Frost Protection:
The client required a foundation solution that resisted frost heave without the cost and site disturbance of a traditional 1.2m deep trench excavation.
2. The Engineering Solution
We developed an OBC Part 4–compliant structural package tailored to the project’s loading conditions with an emphasis on constructability.
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a. Reinforced Slab-on-Grade:
A reinforced slab-on-grade was designed to transfer concentrated steel point loads using thickened edges and bearing pads at HSS post locations, controlling settlement under combined vehicle and gravity loads.
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b. Frost-Protected Shallow Foundation (FPSF):
An FPSF system was detailed using vertical and horizontal rigid insulation to meet frost protection requirements while minimizing excavation and concrete volume.
3. The Outcome
The project architect received a fully stamped, permit-ready structural package that satisfied OBC part 4 compliance and building standards. The solution provided the client with a cost-effective, durable foundation capable of supporting the structure’s complex load path.