How Much Does It Cost to Build a Deck?
A deck quote is a bundle of structure, access, finish, and approval work—not just a price per square foot. Two decks with similar floor area can cost very different amounts when one is low and freestanding while the other is elevated, attached to the house, reached by stairs, or built on difficult ground.
What the project may include
Separate the quote into site and foundations, posts and beams, joists and decking, ledger or other house connection, stairs, guards and handrails, finishes, demolition, disposal, access, design, and approvals. Lighting, skirting, drainage, and a roof are usually add-on scopes rather than automatic parts of a basic deck.
The American Wood Council’s DCA 6 guide organizes a prescriptive wood-deck design around these component relationships. It is based on a stated U.S. code context and assumptions, so it is useful for understanding scope but does not establish that a particular existing structure is adequate or that the same details apply in Canada.
U.S. price signals and why they disagree
2026 summaries from Angi put professional deck building at roughly USD 4,340–12,653, while HomeAdvisor reports a broader roughly USD 4,000–16,000 range. These are different market signals with different definitions, regions, and inclusions. Treat them as orientation for U.S. planning, not as a national price or a substitute for bids. Canadian pricing should come from Canadian quotes or market evidence; do not convert either U.S. range into CAD.
The biggest quote drivers
- Elevation and access: Taller supports, stairs, scaffolding, long material carries, and limited equipment access add labor and risk.
- Attachment: An attached deck may require wall access, flashing, and careful treatment of the house connection. A freestanding design changes the structural and site scope rather than simply removing one line item.
- Foundations and soil: Excavation, rock, roots, slope, drainage, and difficult access can dominate the foundation allowance.
- Finish and geometry: Composite or PVC decking, unusual shapes, multiple levels, detailed railings, and built-in features increase material and installation time.
- Hidden or adjacent work: Demolition, disposal, electrical, grading, drainage, and repairs discovered during excavation may be excluded from a headline price.
How to compare bids
Ask each contractor to identify the deck footprint and elevation, material and grade, framing assumptions, foundation approach, stairs and guards, attachment and flashing, demolition, disposal, finishes, permits, design or engineering, taxes, and allowances. Check whether a price is for a complete permitted project or only the visible deck surface.
For a Canadian project, ask which provincial or territorial requirements and municipal approvals were used. Toronto’s deck and porch guide illustrates why a local application can involve footings, columns, beams, stairs, guards, a site plan, setbacks, and an administrative fee. That example should not be generalized to every municipality.
Bottom line
Use the published ranges to understand order of magnitude, then compare normalized scopes. The useful question is not “What is the average deck price?” but “Which structural, site, access, finish, and approval assumptions are included in this quote?”