The garage is full, the holiday bins are in the hallway, and there's a whole empty attic overhead. Before you buy plywood for a storage platform, check what the roof structure was designed to carry. Those boxes add up, especially the ones nobody wants to lift.
A ceiling structure is not automatically a storage floor
The Structural Building Components Association's load-path explanation explains how loads and bearing points belong to the truss design. Ask for the original design information and an assessment of the proposed storage area. The guide supplies background, not a capacity calculation for your Ontario house.
Count the practical losses too
Safe access, service routes, insulation depth, and attic ventilation can all restrict the usable area. Do not compress insulation to make a larger platform or treat the ceiling between members as a walking surface. Describe what you actually want to store; dense books are different from empty luggage.
Before the next step
- Retrieve the truss drawings where available.
- List the intended items and their approximate combined weight.
- Have access, insulation, and storage loading considered together.
Have the approved storage area and its limits written down, then choose bins that suit it. You want somewhere useful to put the decorations, without creating a bigger job above the ceiling.