Decks, Sheds, and Driveways in Markham — The Permit Rules Every Homeowner Forgets
Every summer, Markham homeowners plan backyard improvements and proceed without checking whether a permit is required. The consequences range from an awkward negotiation at resale to a formal stop-work order. Michael John Lau explains exactly which structures need a permit, where the thresholds are, and what unpermitted work costs you at resale.
Every summer, Markham homeowners enthusiastically plan backyard improvements — a new deck, a larger shed, an extended driveway, or a fence upgrade — and proceed without checking whether a building permit is required. The consequences range from an awkward conversation at resale (when a buyer’s home inspector identifies unpermitted work) to a formal stop-work order from the City, an order to demolish, or complications with home insurance claims. Michael John Lau, top real estate agent in Markham Ontario, has seen all of these outcomes. This is the complete, up-to-date guide to Markham’s permit rules for common home improvement projects.
Decks — The Most Commonly Unpermitted Structure
You need a building permit for your deck if it is:
- More than 600 millimetres (2 feet) above the existing ground level at any point
- Attached directly to your house (regardless of size or height)
- Larger than 10 square metres (approximately 108 square feet) in area
The 600mm rule catches most homeowners: Even a ground-level deck that is attached to the house through a ledger board connection — as virtually all “attached” decks are — requires a permit. The connection to the house structure triggers the permit requirement regardless of height or size. Creating a freestanding rear yard deck that is less than 10 sq m AND less than 600mm above ground AND not attached to the house does not require a permit.
The permit process for a standard attached deck typically requires: a site plan showing the deck location relative to property lines, deck plan drawings with dimensions, the deck’s structural framing plan, and confirmation of setback compliance. Processing time: typically 10 to 20 business days for a complete, correctly submitted ePLAN application.
Sheds and Accessory Buildings — The 10 Square Metre Rule
A new shed or accessory building does not require a building permit if its footprint is less than 10 square metres (108 square feet). Anything larger requires a permit. A standard 12-by-16 foot shed (192 sq ft) requires a permit. The footprint is calculated from the outer walls, not interior dimensions.
Beyond the permit threshold, shed placement must respect zoning setbacks: typically 0.6 to 1.2 metres from interior side and rear property lines in most Markham residential zones. Corner lots have additional setback requirements. Heritage district properties — Unionville, Markham Village, Thornhill, Buttonville — require heritage review for any accessory structure visible from the street, in addition to the standard building permit.
Neeraj Moolchandani, REALTOR® at Kaizen Real Estate, identifies unpermitted work as a standard component of the property assessment for every buyer client — specifically the deck-to-permit record check, the ESA sticker verification on electrical panels, the basement renovation ceiling permit sticker check, and the structural flag for oversized sheds. His pre-offer property review helps buyers understand the disclosure and negotiation implications of any unpermitted work before an offer is structured. Contact the Kaizen Real Estate Team at (647) 370-8885.
Driveways — The Impervious Surface Rules
Driveway resurfacing does not typically require a building permit. However, several driveway situations do require permits or approvals:
- New curb cut: A new vehicular access point to a public road requires a permit from York Region or Markham Public Works (depending on the road classification)
- Driveway widening: Many Markham residential zones limit the percentage of the front yard covered by impervious surface (typically 50% or less). Widening that exceeds this requires zoning compliance review
- Impervious surface limits: If your expanded driveway, deck, shed, and house footprint collectively exceed the permitted lot coverage, a minor variance from the Committee of Adjustment is required before permits can be issued
Fences — Rules Most Homeowners Discover at the Wrong Moment
Fence installation does not require a building permit but must comply with the City’s Fence By-law: a rear yard fence can typically be up to 1.8 metres (6 feet) in height. A side yard fence that extends forward of the front wall of the house must comply with the lower height limit for front yard fencing — typically 0.9 metres (3 feet) in the front yard projection area. Corner lot fences face sight-line triangle restrictions near the intersection. Heritage district fences must be compatible with the heritage character of the district and may require heritage review.
The Disclosure Issue at Resale
For sellers, unpermitted work is a material fact that must be disclosed to buyers. A deck built without a permit, an oversized shed never permitted, or a basement renovation without permits — all must be disclosed on the Seller Property Information Statement and cannot be concealed. A home inspector reviewing a Markham property will identify unpermitted work through visible indicators — decks not connected to permits on file, electrical panel work without visible ESA stickers, basement renovations without ceiling permit stickers. When the inspector’s report flags unpermitted work, the buyer can negotiate a price reduction, request retroactive permits, or rescind the offer.
Retroactive permits — possible in Markham but typically requiring the opening of walls or ceilings for inspector verification — consistently cost more than upfront permitting would have. Michael John Lau, top real estate agent in Markham Ontario, advises seller clients on addressing permit issues before listing to avoid negotiation complications.
Michael John Lau is a licensed REALTOR® and CPA/CMA at Kaizen Real Estate (eXp Realty, eXp Luxury), serving buyers and sellers in Markham, Ontario and across York Region. Licence #4784577. Office: 8763 Bayview Avenue #127, Richmond Hill, ON. Neeraj Moolchandani is a licensed REALTOR® at Kaizen Real Estate, specializing in residential and investment real estate across Markham and York Region. Permit requirements are administered by the City of Markham and are subject to change. Verify current requirements at markham.ca/building-permits or by calling 905-475-4870 before beginning any project.
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