Do You Need a Permit to Build a Deck in Newmarket?

Short answer: In most cases, yes. In Newmarket, a deck generally needs a building permit if it’s more than 600 mm (about 24 inches) above grade or larger than about 10 m² (100 sq ft). But there’s a step unique to Newmarket that catches many homeowners off guard — a Zoning Preliminary Review you have to clear before you can even submit the permit application. Here’s how the whole process actually works. 

When does a deck need a permit in Newmarket?

You’ll generally need a building permit from the Town of Newmarket if your deck is:

• More than 600 mm (about 24 inches) above grade, or
• Larger than about 10 m² (roughly 100 sq ft), or
• Attached to your house.

A guard (railing) is required once the deck sits more than 2 feet above grade. A small, low, freestanding deck under those thresholds may not need a permit — but it still has to comply with the Town’s Zoning By-law (setbacks and lot coverage). “No permit required” never means “no rules.” 

The step most people miss: Newmarket’s Zoning Preliminary Review

This is where Newmarket differs from many municipalities. Before you submit a building permit application for a deck, the Town requires a Zoning Preliminary Review — a check that your proposed deck meets the zoning rules (setbacks, lot coverage, height) for your property’s specific zone.

Two things worth knowing:

• The Zoning Preliminary Review has its own fee, but it’s credited toward your building permit fee once the permit is processed — so it isn’t an extra cost, just an extra step.
• It happens first. Skipping straight to the permit application is the most common reason a Newmarket deck project stalls at the counter.

To find your property’s zone before you start, use the Town’s “What’s My Zoning” / Navigate Newmarket tool. 

What are the setback and zoning rules?

Your deck has to meet the minimum distances from your front, rear, and side property lines set by the Town of Newmarket Zoning By-law — and those depend on the zone your property falls in, not a single town-wide number. The Zoning Preliminary Review above is exactly what confirms these for your lot. 

What does the Ontario Building Code require for the deck itself?

Beyond zoning, the deck’s construction has to meet the Ontario Building Code, which applies province-wide:

• A guard is required once the deck surface is more than 600 mm (24 in) above grade.
• 600–1800 mm above grade: guard at least 900 mm (36 in) high.
• Above 1800 mm: guard at least 1070 mm (42 in) high.
• No opening in a required guard may let a 100 mm (4-inch) sphere pass — the most-failed inspection item, so baluster spacing matters.
• Stairs need a graspable handrail on at least one side.
• Footings sized and dug deep enough for frost and load.

What’s the permit process in Newmarket, step by step?

1. Find your zoning using the Town’s “What’s My Zoning” tool.
2. Zoning Preliminary Review — submit for the zoning check first.
3. Prepare your drawings — a site plan showing the deck and its distances to each property line, plus construction drawings (footings, framing, guards).
4. Submit the building permit application through the Town’s online Development Portal.
5. Build to the approved plans and book inspections (contact the Town’s inspections line about two days ahead).

Do you need a permit to replace an existing deck?

Often yes — especially if you’re changing the size, height, or structure. A like-for-like surface refresh may differ. Confirm with the Building Division before starting.

Building a deck in Newmarket? We handle the permit for you.

Forest Fence & Deck has built custom decks across Newmarket since 1984. We confirm your zoning, handle the Zoning Preliminary Review and the building permit, and coordinate inspections — so you get the deck without the paperwork.

See our Newmarket deck services → · Call 905-841-6664 for a free consultation.