Building · Cost Guide
How Much Does Decks Cost in Ontario?
Decks costs in Ontario range from $5,000 – $10,000 per project. Prices vary by scope, city, and site conditions.
$5,000+
Starting price
3-10 days
Timeline
10%
Recommended contingency
Interactive 3D Deck Model
Explore a typical 8′ × 10′ deck build step by step — footings through railing.
Decks Cost Breakdown
| Scope | Low | High | Unit | Labour | Material |
|---|---|---|---|---|---|
| Pressure-treated wood deck (200 sq ft) | $5,000 | $10,000 | per project | 50% | 50% |
| Composite deck (200 sq ft) | $10,000 | $20,000 | per project | 45% | 55% |
| Cedar deck (200 sq ft) | $8,000 | $15,000 | per project | 50% | 50% |
| Deck repair/re-decking | $2,000 | $6,000 | per project | 55% | 45% |
| Railing installation | $50 | $150 | per lin. ft | 50% | 50% |
| Small deck 8×10 (80 sq ft) | $2,500 | $5,000 | per project | 45% | 55% |
| Multi-level deck (300+ sq ft) | $18,000 | $40,000 | per project | 50% | 50% |
| Rooftop/balcony deck | $15,000 | $35,000 | per project | 55% | 45% |
| Deck with built-in features (benches, planters, lighting) | $12,000 | $30,000 | per project | 50% | 50% |
| Hot tub deck pad (reinforced) | $3,500 | $8,000 | per project | 55% | 45% |
| Deck staining/sealing (annual) | $400 | $1,200 | per project | 60% | 40% |
Price Ranges at a Glance
Pressure-treated wood deck (200 sq ft)
Composite deck (200 sq ft)
Cedar deck (200 sq ft)
Deck repair/re-decking
Railing installation
Small deck 8×10 (80 sq ft)
Multi-level deck (300+ sq ft)
Rooftop/balcony deck
Deck with built-in features (benches, planters, lighting)
Hot tub deck pad (reinforced)
Deck staining/sealing (annual)
What's Included vs Not Included
Typically Included
- Concrete footings (below frost depth)
- Post and beam structure
- Deck boards and fasteners
- Railing and stairs
- Building permit
- Ledger board flashing
Not Included (Extra Cost)
- Outdoor electrical (lighting, outlets)
- Pergola or shade structure
- Built-in benches or planters
- Hot tub pad and wiring
- Old deck removal ($1,000-$3,000)
- Privacy screens and wind barriers
Decks Cost by City
Prices adjusted for local labour rates and material costs across 15 GTA cities.
| City | Low | High | vs Toronto | Details |
|---|---|---|---|---|
Toronto City of Toronto | $5,000 | $10,000 | 0% | View |
Mississauga Peel Region | $4,775 | $9,550 | -5% | View |
Brampton Peel Region | $4,650 | $9,300 | -8% | View |
Vaughan York Region | $4,875 | $9,750 | -3% | View |
Markham York Region | $4,850 | $9,700 | -3% | View |
Richmond Hill York Region | $4,825 | $9,650 | -4% | View |
Aurora York Region | $4,725 | $9,450 | -6% | View |
Oakville Halton Region | $5,075 | $10,150 | +2% | View |
Burlington Halton Region | $4,800 | $9,600 | -4% | View |
Milton Halton Region | $4,650 | $9,300 | -8% | View |
Ajax Durham Region | $4,575 | $9,150 | -9% | View |
Pickering Durham Region | $4,650 | $9,300 | -8% | View |
Oshawa Durham Region | $4,475 | $8,950 | -12% | View |
Whitby Durham Region | $4,550 | $9,100 | -10% | View |
Hamilton City of Hamilton | $4,525 | $9,050 | -10% | View |
Permit & Engineering Costs
Building permit
Municipal building department
Required for decks more than 24 inches (600mm) above grade in most Ontario municipalities
$200-$800
ESA electrical permit
Electrical Safety Authority
If adding outdoor outlets, lighting circuits, or hot tub wiring
$100-$200
Committee of Adjustment
Municipal planning
If your deck exceeds lot coverage or setback limits
$1,500-$3,000
Money-Saving Tips
Composite costs 2x upfront but needs no staining/sealing — breaks even at year 8-10.
Footings must go below frost line (4 ft in Southern Ontario) — shallow footings heave and crack.
Pressure-treated needs annual staining ($500-$1,000) — factor maintenance into lifecycle cost.
A permit is required for any deck over 2 ft above grade or over 100 sq ft in most GTA municipalities.
Build during fall for 10-15% off peak-season spring/summer pricing.
Toronto frost depth requires footings at minimum 4 feet (1.2m) below grade with sonotubes — mandatory inspection before concrete pour.
Toronto building permit for decks costs $350-$600 with 2-4 week approval and mandatory footing + final inspections.
Ravine lot decks require TRCA environmental review adding $2,000-$5,000 and 8-12 weeks — check trca.ca before planning.
Composite saves $800-$1,500 in maintenance over 20 years vs pressure-treated wood requiring biennial staining.
Deck cost per square foot decreases with size: 100 sq ft runs $60-$80/sq ft while 300 sq ft drops to $45-$65/sq ft.
Related Cost Guides
Decks Cost FAQs
Do I need a permit for a deck in Ontario?
Yes, if your deck is more than 600mm (about 24 inches) above adjacent grade. Some municipalities require permits for any attached deck regardless of height. Building without a permit is illegal — you must disclose unpermitted work when selling, and if there's an injury, you face personal liability. A permitted deck costs the same to build and you get the benefit of professional inspections.
How long does a deck last?
A well-built, well-maintained pressure-treated deck lasts 15-25 years. Cedar lasts 15-20 years with regular staining. Composite decking lasts 25-30+ years with minimal maintenance. However, these numbers assume the structure underneath is sound. Fasteners, joist hangers, and connections can fail before the wood shows visible damage. Inspect the underside annually — that's where problems hide.
Can I build a deck myself?
You can, but you still need a permit and must pass inspection. The building code doesn't care who builds it — it cares that it's built right. Common DIY mistakes: using nails instead of bolts for the ledger (collapse risk), not going deep enough on footings (frost heave), notching guard posts (failure under load), and inconsistent stair risers (fall hazard). If you DIY, get the IRC Prescriptive Residential Deck Construction Guide (DCA 6) — it's free and tells you exactly how to build a code-compliant deck.
What's the difference between pressure-treated, cedar, and composite decking?
Pressure-treated lumber is the cheapest ($3-$5/sq ft for boards) and lasts 15-25 years but needs staining every 2-3 years. Cedar costs more ($6-$10/sq ft), looks better, and is naturally rot-resistant but still needs maintenance. Composite ($8-$15/sq ft) never needs staining and won't rot, but costs 2-3x more upfront. All three use the same structural framing underneath — the decking is just the surface. Don't cheap out on the structure to afford nicer decking.
My deck is old but looks fine — is it safe?
Maybe not. Most people only look at the top of their deck. The dangerous defects are underneath — corroded joist hangers, rotted ledger connections, loose guard posts, and deteriorated fasteners. A deck built before 2006 was likely built under a code with almost no prescriptive guidance for decks. If your deck is 15+ years old, get under it with a flashlight and look for red rust on metal, soft or discolored wood, and connections that have pulled apart. Better yet, hire a home inspector who specializes in decks.
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