Deck Cost Calculator (DIY materials)

Your Deck

Materials Breakdown

How this estimate works

Deck + framing = area × the material rate you set (framing, decking boards, and hardware). Railings = railing length × your per-foot rate, where railing length is the perimeter minus the house side for an attached deck (and minus a ~4 ft stair opening when stairs are included). Stairs = number of steps × your per-step rate, with steps estimated from deck height at a ~7.5″ rise. A waste/extras percentage is applied to those materials, then your editable foundation allowance is added. The result is shown ±15%. Labour is excluded — supplying it yourself is the main DIY saving (roughly 40–50% of a built deck).

What drives the number

Decking material is the headline choice and the widest spread on the page. Pressure-treated lumber is the cheapest way to get a deck and the most maintenance-hungry. Cedar costs more and weathers better. Composite and PVC cost substantially more upfront and effectively eliminate the annual sanding-and-staining ritual. The right comparison is total cost over the years you'll own it, including the weekend each spring — our decking materials comparison puts the lifespans and maintenance loads side by side.

Railings cost far more per foot than the deck surface, which surprises nearly everyone. A railing is posts, rails, balusters or panels, and the connections that make it strong enough to lean on — and code sets both the required height and the load it has to resist. Long, narrow decks have much more perimeter per square foot than square ones, so shape alone can move the railing bill significantly. Glass or cable infill multiplies it again.

Height is the hidden cost multiplier. A deck 600 mm off the ground and a deck 2.5 m off the ground have the same area and very different prices: taller posts, deeper footings, bracing, more stair steps, and — past a threshold set by your code — mandatory guards. Height also determines whether you need a permit at all in many municipalities.

Stairs are priced per step, and step count comes from height, not from the deck's footprint. Going up a metre roughly doubles the stair cost of going up half a metre. Landings, turns, and a second stair run add more.

Labour is excluded here, and it's roughly 40–50% of a professionally built deck. That's the DIY saving, and it's real — a deck is one of the more approachable structures to build yourself. It's also the project where the connection details matter most, which is why the ledger and railing sections of the deck permits and code guide are worth reading before you start rather than after.

What this estimate does not include

• Labour, as above — this is a materials estimate with a foundation allowance.
• The permit, and the drawings some municipalities require with it. Most jurisdictions require a permit above a certain height or area.
• Detailed footing costs. The foundation allowance here is a placeholder — size it properly with the Deck Foundation Cost Calculator, which accounts for your local frost depth.
• Ledger attachment and flashing where the deck meets the house. Improperly flashed ledgers rot the house's rim joist, and ledger failure is the leading cause of deck collapses. Not a place to improvise.
• Site preparation: removing an old deck, grading, or dealing with what's under the new one — landscape fabric, gravel, or drainage if water collects there.
• Finishing: stain, sealer, or paint on PT and cedar, plus the recurring cost of redoing it.
• Extras that arrive late in the design: built-in benches and planters, privacy screens, skirting, under-deck storage or drainage, lighting, and electrical for a hot tub — which also brings a structural load calculation with it.
• Hot tubs and heavy loads generally. A standard deck is not designed for one; adding it after the fact usually means additional footings and framing.

For what a finished deck costs installed across Canada, see Deck Cost in Canada.