In King Township, a freestanding deck 60 cm or lower needs no building permit, but any deck attached to a building does, at any height. Typical new decks run about $30 to $80 per square foot in the Toronto area.
Out in King City, Nobleton and Schomberg the deck is rarely a small platform off a patio door. It is a long back deck on a big lot, a raised walkout off a hillside house, or a wraparound porch that has taken a decade of frost, sun and snow shovels. Repairs on that scale are different from a suburban lot in two ways: more of the structure is exposed, and more of the rules depend on how the deck is attached and how high it sits. This guide sticks to what King's own Building Division says and what the Ontario Building Code requires, and it is honest where a number or a rule could not be confirmed.
The permit line: 60 cm, and "attached" changes everything
King Township's Residential Deck Structure Application Guide states two things plainly. A building permit is required for any deck or porch attached to a building, regardless of area or height above grade. A building permit is not required if a deck does not exceed 60 centimetres (about 23.6 inches) above grade and is not attached to another structure. It adds that every deck, whatever its size or height, must comply with applicable law and the Zoning By-laws.
So a low freestanding deck out in the paddock-side garden can be rebuilt without a permit, while the big deck bolted to the back of the house is permit territory. The guide is written for building a deck, and it does not spell out whether swapping a handful of worn boards on an existing attached deck counts. Replacing decking boards is cosmetic; replacing posts, beams, the connection to the house, or footings is structural. For anything structural on an attached deck, phone the Building Division at 905-833-5321 and ask before you start, and ask for the answer in writing if the work is large.
Approvals that can come before the permit
On a large rural property the permit is often not the slow part. The Township's guide says the Building Code Act prohibits issuing a permit if the work would contravene applicable law, and that applications without the required applicable-law documentation will not be processed. Its examples of approvals to check first include:
- A Zoning Certificate from the Township's Planning Department.
- Site plan approval or agreement, where one applies.
- An approval or permit from the Lake Simcoe Region Conservation Authority or the Toronto and Region Conservation Authority. Much of King sits in one of those watersheds, and a deck near a creek, pond or valley slope is the classic case.
- A minor variance from the Committee of Adjustment if the deck breaks a setback or lot-coverage limit.
- An approved grading plan from the Township's Development Engineering Department.
The same guide asks for a survey or site plan showing existing structures, the proposed deck and distances to property lines, and on rural lots it specifically asks for the septic tank and bed to be shown. That matters in practice: decks are often built right where the leaching bed or a tank access lid is. Never put new footings or a heavy structure over a septic bed, and keep lids reachable. Our septic guide for King Township explains the layout.
What drawings the Township wants
For a permit application the guide asks for foundation and deck plans showing footing size and spacing, joist and beam sizes and spans, stairs, elevations of every side with height above average grade, and sections showing footing depth, guard height and how the deck connects to the house. Drawings from a qualified designer carry a BCIN number; the guide says homeowners may prepare their own drawings for a residential deck but must complete the exemption part of the Schedule 1 form. Fees are set by the Township's fee by-law, and the guide lists a municipal security deposit for work on lots fronting municipal roads, so ask what applies to your lot.
Guards: the repair most likely to matter for safety
On a raised walkout deck the guard is the part to inspect first. Ontario Building Code 9.8.8.1 requires a guard on each open side of a deck, porch or balcony where the drop between the walking surface and the adjacent surface is more than 600 mm (about 23.6 inches). Two design rules also apply, as published in municipal builder tips that quote the Code: openings in standard baluster guards are limited to 100 mm (about 4 inches), and under 9.8.8.6 nothing between 140 mm and 900 mm above the deck surface should make the guard easy to climb. Horizontal rails that act like a ladder are the usual failure. The exact required guard height depends on the height of the deck and the Code edition, so confirm it with the Building Division rather than copying a number from the internet.
A wobbly guard post is not a cosmetic issue. If posts are only screwed to the face of the rim joist and flex when you lean on them, treat it as a repair to do before the next gathering, and have it done to the Code rather than patched.
Repair, resurface or replace: a practical test
- Surface boards only: soft spots limited to a few boards, solid framing underneath. This is a boards-and-fasteners job.
- Framing questions: a screwdriver that sinks into joists or beams, rot at the post bases, sagging mid-span, or a ledger (the board fixing the deck to the house) that is soft, pulling away or leaking. These make it a structural repair and, on an attached deck, a call to the Building Division.
- Footings: heaved or leaning posts after a hard frost. Municipal deck guides elsewhere in Ontario, such as Barrie's, put frost-protection footing depth at about 4 feet below grade; King's guide asks for footing depth on the drawings, so confirm the figure the Township expects.
What it costs: general market estimates
We could not find a reliable Ontario price for replacing deck boards alone, and the repair figures that exist online are mostly American, so none are quoted here. What is published for the GTA is the cost of new work. A Toronto deck builder's 2026 guide gives installed new-deck prices of roughly $30 to $50 per square foot for pressure-treated wood, $45 to $65 for cedar and $55 to $80 for composite. The same guide lists installed railing at about $55 to $65 per linear foot in pressure-treated wood and $80 to $120 for basic aluminum, and puts removing an old deck at about $500 to $2,500. Those are general estimates for the Toronto area, not King Township prices and not quotes, so a long rural rail run or a hillside deck can sit well outside them. Rural travel, a longer reach for materials and framing repairs found once boards come up are the usual reasons real quotes move. Get written quotes that separate boards, framing, railing and any permit work, and add 13% HST.
Before anyone digs or drills
Resetting footings is digging, so request locates from Ontario One Call before the first hole; rural driveways and road frontages often hide gas, hydro and telecom lines. Our fence and gate repair guide covers the same locate rule.
Quick answers
Do I need a building permit to repair a deck in King Township?
Not for a freestanding deck 60 cm (about 23.6 in) or lower. The Township requires a permit for any deck attached to a building at any height, so call the Building Division at 905-833-5321 before structural repairs.
How high can a deck be in King Township before it needs a permit?
The Township's guide says no permit is needed if the deck does not exceed 60 cm above grade and is not attached to another structure. Zoning by-laws still apply to every deck.
When does a deck need a guard in Ontario?
Under Ontario Building Code 9.8.8.1, a deck needs a guard on each open side where the drop to the adjacent surface is more than 600 mm, about 23.6 inches. Guards also must not be easy to climb.
How much does a new deck cost in the Toronto area?
A Toronto-area contractor guide puts installed decks at about $30 to $50 per square foot for pressure-treated wood and $55 to $80 for composite. These are general 2026 estimates, not repair prices.
Who can I call to repair a deck in King City?
Rhodex can send a vetted craftsman; request a quote at rhodex.ca/get-a-quote.html. Ask that the quote say who checks the permit question.
A short checklist
- Is the deck attached to the house, or higher than 60 cm? If so, call the Building Division first.
- Are the guards solid, no more than 100 mm between balusters, and not climbable?
- Is anything near a creek, pond or slope, or over the septic bed?
- Is the ledger sound? Is framing solid under the boards?
- Have locates been requested before any post holes?
Sources
- Township of King, Building Division, Residential Deck Structure Application Guide (February 2026 package)
- Ontario Building Code, Sentences 9.8.8.1 and 9.8.8.6, as quoted in City of Markham and Township of Perry builder tips
- Decks For Life, "How Much Does a Deck Cost in Toronto in 2026?"
- City of Barrie, deck footing detail
Related reading
- More home repair guides for King Township
- Fence and Gate Repair on a King Township Estate Lot
- Septic System Maintenance and Small Repairs in King Township
- Barn, Stable or Outbuilding Repair in King Township
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