Composite deck quote at $45 a square foot in Nepean: too low?

$45 a square foot sits at the very bottom of the published range for composite decks in Ottawa and Ontario, which runs from about $45 to $95 per square foot installed. A quote at the bottom of the range is worth checking line by line, so the first job is to find out exactly what it covers.

Published Ottawa and Ontario builder prices, read in September 2026, show a wide spread for composite work. A quote at the floor of that range is not automatically wrong, but several things can explain it.

What the quote may or may not include:

• The composite board line and whether it is a capped wood-plastic product
• Guards and railings, and stairs: some published packages leave these out
• Removal and disposal of an existing deck (the City of Ottawa says wood from demolition, including pressure-treated lumber, is not collected with regular garbage and goes to the Trail Road Landfill Site or another landfill)
• Footings or helical piles and the foundation type suited to your lot
• Permit drawings and the City of Ottawa building permit fee (calculated at $12.75 per $1,000 of assessed project value, minimum $117)

A few Ottawa-specific rules will affect the final cost regardless of the quote. If the deck's walking surface is more than 600 mm (24 in.) above adjacent grade and it is attached to the house, a building permit is required. Where composite decking is proposed, the City requires a material testing report (CCMC or BMEC) with the permit application. Guards on a deck serving one dwelling unit must be at least 900 mm high where the walking surface is not more than 1 800 mm above finished ground, and at least 1 070 mm in other cases, under the 2024 Ontario Building Code. In Ontario, no member, attachment or opening between 140 mm and 900 mm above the walking surface may facilitate climbing, and horizontal rails or cable infill in that zone can facilitate climbing, which is what that rule targets, so confirm any such design with the City.

Zoning also applies. For applications deemed complete on or after March 11, 2026, Ottawa applies both Zoning By-law 2008-250 and By-law 2026-50, with the most restrictive provisions from each applying. Setbacks from lot lines depend on the deck's height above grade, whether it is attached or freestanding, and which yard it sits in. Confirm the rules for your specific lot with the City before finalising the design.

Ask the builder for a written, itemised quote that names every component: the board product and its grade, the framing species and size, the foundation type, guards, stairs, removal, drawings and permit. The Consumer Protection Act, 2002 requires that if an agreement includes an estimate, the supplier may not charge more than 10 per cent above it, so a clear written scope protects both sides.

The contract should name who applies for the City of Ottawa building permit and who books the three required inspections: Excavation/Foundations before backfill, Framing at completion of structural framing and guards, and Final at completion of the deck, stairs and guards. The City says to book inspections 48 hours in advance, and naming who does it in the contract removes any doubt about whose job it is.