A pressure-treated wood deck in Thornhill typically costs $30 to $60 per square foot including labour. Composite decking (Trex, TimberTech, etc.) runs $50 to $100 per square foot. Cedar deck construction falls in the $40 to $80 range. A 300-square-foot deck might cost $9,000 to $30,000 depending on materials, height, complexity, and railing style. Stairs, built-in benches, and pergolas are typically priced separately.
In virtually all Canadian municipalities, a building permit is required for any deck over a certain size or height. Common thresholds are decks over 24 inches above grade, or over a certain square footage (often 10 square metres). Permit approval ensures the deck structure, ledger connection, and footings meet code, which is important for both safety and home insurance coverage.
Composite decking is increasingly popular in Thornhill because it resists moisture, does not require staining, and handles freeze-thaw cycles without warping. Pressure-treated wood is the most economical option and widely available, but requires regular staining. Cedar naturally resists rot and is a mid-range option. For maximum longevity with minimal maintenance in Thornhill's winters, composite is the preferred choice.
A standard ground-level or raised deck of 300 to 400 square feet typically takes three to seven days to build from footing pour to handrail installation. Permit approval and footing inspection can add one to two weeks to the overall timeline. More complex multi-level decks with pergolas or outdoor kitchens can take two to three weeks or longer.
Ask whether the quote includes permit applications, footing inspections, and a structural drawing if required. Confirm the footing depth for Thornhill's frost line (typically 48 inches minimum). Ask about joist spacing, beam sizing, ledger connection method, and railing height compliance with the National Building Code. A detailed written contract specifying all materials is essential.
