Cost to Build a Deck in the GTA (2026): Composite vs Pressure-Treated

A deck is one of the highest-impact additions you can make to a GTA backyard — and one of the easiest to get wrong if you don't budget honestly up front. Here's what a new deck actually costs in 2026, broken down by size, materials, and the line items most quotes forget.

How decks are priced

Decks are typically priced per square foot of deck surface, but that number is a starting point. The real price is built from five components:

1. Footings — concrete sonotubes below the frost line (1.2 m / 4 ft in most of the GTA)
2. Frame — pressure-treated joists and beams, plus structural connectors
3. Decking — the board material you see (PT, cedar, or composite)
4. Railings, stairs, skirting — often half the visible build
5. Permit, engineering, and finishing — paperwork and the last 10% of finish work

A 200-square-foot rectangular deck that's two stair-steps off the ground will quote very differently from a 200-square-foot multi-level deck with a stair to grade and a pergola — even though the surface area is identical.

Pressure-treated deck cost — 2026 GTA ranges

A standard pressure-treated (PT) deck, fully installed, runs $45 to $70 per square foot in the GTA right now. For a typical 16' × 12' deck (192 sq ft):

• Materials (PT joists, beams, decking, hardware): ~$3,800
• Labour: ~$5,500
• Concrete footings and digging: ~$1,400
• Railings and one set of stairs to grade: ~$2,200
• Permit fee (typical GTA): ~$300

Total: roughly $13,000–$15,000 for that footprint, including everything but a custom railing or pergola.

A larger 20' × 14' PT deck (280 sq ft) at the same spec runs closer to $18,000–$22,000.

Composite deck cost — 2026 GTA ranges

Composite (Trex, TimberTech, Fiberon, Deckorators) costs more in material but the same in labour and footings. Per-square-foot installed ranges:

• Entry composite line (Trex Enhance or equivalent): $65–$85 per sq ft installed
• Mid composite (Trex Transcend, TimberTech Edge): $85–$110 per sq ft installed
• Premium composite (TimberTech AZEK PVC, Trex Transcend Lineage): $110–$145 per sq ft installed

For the same 16' × 12' footprint:

• Entry composite: $16,000–$18,500
• Mid composite: $18,500–$23,500
• Premium composite: $23,500–$30,000

The frame underneath a composite deck is still pressure-treated wood — the composite is only the visible boards and (usually) the fascia.

Labour, permits, and the line items quotes leave out

Outside materials, here's where deck quotes hide cost:

• Engineering drawings ($600–$1,500): often required for decks over 24" or attached to the house in Toronto, Vaughan, Mississauga, and Markham.
• Permit fees ($250–$600): vary by city and deck size.
• Soil disposal: footings dig out 30–60 bags of soil. Disposal is $300–$800.
• Aluminum railing system upgrade: $80–$130 per linear foot vs. wood at $25–$45.
• Glass-panel railing: $200–$280 per linear foot. Looks amazing, painful on the budget.
• Skirting / lattice / under-deck storage: $400–$1,800 depending on length.

When a quote looks suspiciously low, check whether engineering, permit, and disposal are included or "by owner." If they're not in writing, they're not in the price.

5- and 15-year cost-of-ownership comparison

Let's compare the same 200 sq ft deck across 15 years:

Pressure-treated:

• Build: $13,500
• Year 2 (first proper stain/seal): $400
• Years 5, 8, 11, 14 (re-stain): $400 × 4 = $1,600
• Year 10 (replace 2–3 worst boards + handrail): $1,200
• 15-year total: ~$16,700

Mid-tier composite:

• Build: $21,000
• Years 2 and 8 (pressure wash): $200 × 2 = $400
• Year 10 (replace 1–2 boards if any): $400
• 15-year total: ~$21,800

After 15 years, the cost gap narrows from ~$7,500 to ~$5,100 — and the composite still looks 80% new while the PT looks 15 years old.

For homes you plan to stay in 10+ years, Reformity's decking team recommends composite. For homes you plan to sell within 5–7 years, PT delivers more deck-per-dollar and the buyer doesn't pay an obvious premium for composite.

Permit reality in the GTA

In every GTA municipality, a deck attached to the house, taller than 24" off the ground, with a structural railing, requires a building permit. Most cities also require engineering stamps when the deck has stairs descending more than three steps to grade.

The permit process generally looks like:

1. Site sketch and structural drawings prepared (we do this)
2. Submission to the city's building department
3. Plan review (1–4 weeks depending on city; Brampton ~2 weeks, Toronto ~3 weeks)
4. Permit issued; we book footing inspection
5. Footing inspection passes; we frame
6. Framing inspection passes; we finish
7. Final inspection; permit closed

Building without a permit is a bad idea. The penalty is double the permit fee plus a stop-work order if the city catches you mid-build. Worse, when you sell the house, the buyer's lawyer will pull a Compliance Letter from the city and any unpermitted structure becomes a closing problem.

How Reformity quotes a deck

We do a free in-home consult — we measure the space, talk through how you'll actually use the deck (entertaining? hot tub? kids?), discuss material and railing options, and identify any drainage or grading issues. Within 48 hours you get a written quote with:

• Line-item materials list with brand names
• Footing count and depth
• Permit fee included
• Engineering drawing fee included (if needed)
• Fixed start date and a Gantt timeline
• Two-year workmanship warranty in writing

We don't quote ranges. The number we send is the number you pay, assuming no change orders.

Ready to price your deck?

If you have a deck project in mind — even just a rough idea — book a free consult. We'll measure, sketch, and price it in writing within 48 hours. For permit-heavy renovations, we also handle interior renovations and can bundle indoor-outdoor projects under one contract if you're planning a bigger refresh.