Do you need a permit for a deck in Ontario?
Usually yes, if any part of the deck is more than about 600 mm (24 in) above the ground or it has a roof. Some cities also count decks attached to the house or over a set area. Permit or not, every deck has to meet the Ontario Building Code.
Last verified 2026-10-06What the Building Code checks
- Guards on any side more than 600 mm up: 900 mm high, or 1,070 mm above 1.8 m.
- Footings 1.2 m deep, below the frost line.
- Stairs with 125–200 mm risers and a handrail over three risers.
- A roof, hot tub or privacy wall adds loads that need an engineered design.
Decks by city
The local rule and fee, linked to each City’s own source.
| City | Rule | Fee | Checked |
|---|---|---|---|
| Kitchener | Yes, if the deck is more than 24 in (610 mm) above the ground or has a roof. | $95 flat fee | 2026-10-06 |
| Waterloo | Yes, if the deck is more than 24 in (610 mm) above the ground or has a roof. | $132 flat fee | 2026-10-06 |
| Toronto | Yes, if the deck is more than 60 cm (24 in) above the ground. The City's deck guide says only some detached decks can skip a permit, so plan on one for a deck attached to the house. | $214.79 flat fee | 2026-10-07 |
| Ottawa | Yes, if the deck is attached to or next to the house and more than 600 mm (24 in) above the ground, or if it's a raised deck that's the main way into the house. | $12.75 per $1,000 of construction value, minimum $117 | 2026-10-07 |
| Mississauga | Yes, if the deck is more than 0.61 m (2 ft) above the ground, or it's a covered porch. | $244 | 2026-10-07 |
| Brampton | Yes, if the deck is attached to the house at any height, or 0.6 m (2 ft) or more above the ground. | $326.21 flat fee | 2026-10-07 |
| Hamilton | Yes for any deck attached to the house, whatever its size or height, and for a deck used with a pool. | $5.36 per m² of deck, minimum $291 | 2026-10-07 |
| London | Yes, if the deck is more than 600 mm (2 ft) above the ground, or attached to the house at any height. | $260.37, or $368.85 if it holds up a roof | 2026-10-07 |
| Oakville | Yes for any deck attached to the house. A freestanding deck needs one if it's bigger than 10 m² and more than 61 cm above the ground. | $220 | 2026-10-06 |
| Cambridge | Cambridge gives no deck height rule. It needs a permit for any structure bigger than 10 m² (108 sq ft), which covers most decks. | $143 ($118 permit plus a $25 zoning review) | 2026-10-07 |
| Guelph | Yes, if any part of the deck floor is 0.6 m (24 in) or more above finished grade, attached or not. | $160 flat fee | 2026-10-07 |
What you’ll submit
- A site plan with the lot lines, the house and the deck, with distances
- A framing plan: joists, beams, posts and footings with sizes and spacing
- Elevations and sections: guard, stairs, the ledger connection and footing depth
- The application form and the owner or designer declaration
Common questions
From the guide: Ontario deck rules, in plain English
How high does a deck railing need to be in Ontario?
900 mm if the deck is no more than 1.8 m above the ground, 1,070 mm if it's higher. A guard is required on any side more than 600 mm above the ground.
How deep do deck footings need to be in Ontario?
At least 1.2 m below finished ground, on undisturbed soil, so frost can't lift them.
Are horizontal deck railings allowed in Ontario?
Not on a required guard. Horizontal rails are climbable, and the code doesn't allow anything that helps a child climb between 140 mm and 900 mm above the deck.
Can I use deck blocks in Ontario?
Only for a small, low, freestanding, uncovered deck: up to 55 m² with joists no more than 600 mm above the ground.
What stair rise is allowed for a deck?
Each riser is 125–200 mm, and all risers are within 5 mm of each other. Runs are 255–355 mm.
Start with what you have.
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