A tree through the deck looks wonderfully established. It can also be an expensive way to discover that a trunk opening and a tree-protection plan are different things.
Start below the photograph
Bring the proposed footing locations and construction access route to the arborist and designer. Include staging areas, not just the final deck perimeter. The crew needs somewhere to put materials long before anyone sits in the shade.
Oakville's town-tree construction procedure addresses protection zones and construction activity around municipal trees. Private-tree requirements and any applicable approvals need their own check; do not apply a town-tree rule to every tree without asking.
Leave the layout negotiable
A symmetrical beam grid may conflict with a root that matters. Moving a support can then change a beam or cantilever. Let the arborist's findings and structural design meet before ordering materials.
Design for next year too
- How will the opening accommodate growth without the boards rubbing the trunk?
- Can leaf litter be removed from the deck and drainage routes?
- Will anyone be tempted to fasten lights, beams, or a privacy screen to the tree?
- Can the tree be maintained after the deck is complete?
The town's deck guidance provides the separate building and zoning starting point. A tree-friendly layout still needs a buildable deck design.
The practical next step is to let the tree interrupt the geometry. The garden already has something valuable. A slightly less dramatic deck is a reasonable price for keeping it.