Do You Need a Permit to Build a Fence, Deck, or Pergola in Ontario?

Welcome back to Digging Deeper with The Post Hole Company!

This is the question almost every homeowner asks before they start an outdoor project — and it’s one of the most important questions you can ask, because getting it wrong is expensive. Building without a permit when one was required means stop-work orders, fines, forced demolition, and real estate headaches when you go to sell.

We’re not engineers or building inspectors. But after 16-plus years of digging holes for fences, decks, pergolas, gazebos, and pool enclosures across Mississauga, Burlington, Hamilton, Brampton, Oakville, and the wider GTA, we’ve seen every permitting scenario there is. This post covers what you need to know before the first hole gets dug.

One important note upfront: municipal bylaws vary across the GTA, and they change. This post reflects current Ontario Building Code (OBC) rules and general municipal practice as of 2025/2026. Always confirm the specific requirements with your local building department before you build.

Why Permits Matter — Especially for the Footings

Most people think of a building permit as a piece of paper that allows them to build something. That’s true, but the more important function of a permit is what happens during the build — the inspections.

For any outdoor structure that requires below-grade footings, there is typically a footing inspection before the concrete is poured. The inspector comes to site, looks at the open holes, confirms they are the correct depth and diameter, and signs off. Only then can the concrete go in.

This matters directly to us and to you. If your project requires a permit and a footing inspection, we need to know before we show up to pour. The sequence is:

1. Permit approved
2. We dig the holes
3. Inspector visits and signs off on the open holes
4. We pour the concrete
5. Build proceeds

If we pour before the inspection happens, the inspector may require the concrete to be broken out and the holes exposed again. That is an expensive mistake that is entirely avoidable with a five-minute conversation before we book.

Fences: Usually No Permit — But There Are Conditions

For most standard residential fences in Ontario, a building permit is not required. But “no permit required” does not mean “no rules apply.” Several conditions govern where and how a fence can be built, and getting these wrong can mean a complaint from a neighbour, a bylaw officer visit, or being forced to take the fence down.

Height limits. Most GTA municipalities allow a maximum fence height of 2 metres (about 6.5 feet) in rear yards and 1 metre (about 3.3 feet) in front yards. Some municipalities allow taller rear yard fences with a variance. Check your local bylaw — height rules vary between Mississauga, Burlington, Hamilton, and Brampton.

Location and setbacks. A fence must be built on your property, not your neighbour’s. It also cannot obstruct sightlines at a corner intersection. Your municipality may have specific setback rules for fences near the road allowance or near a driveway. Read more about why knowing your property line matters in our post on Know Your Property Line.

Pool enclosure fences. If you are fencing around a swimming pool, a permit is always required regardless of fence height. Ontario’s pool enclosure regulations under the OBC are strict — minimum 1.2-metre fence height, self-closing and self-latching gate hardware, specific requirements around gaps and climbability. These fences also require private locates for pool plumbing and equipment lines before any digging.

When your fence does need a permit. A permit is required if your fence exceeds the permitted height in your zone, if you are requesting a variance, or if the fence is part of a larger permitted structure. Your local building department will confirm.

Decks: Permit Required If the Surface Is More Than 600mm Above Grade

This is the single most important rule to know about deck building in Ontario:

If any part of your deck surface is more than 600mm — that’s about 24 inches — above grade at any point, a building permit is required.

This comes from OBC section 1.3.1.1 and the Building Code Act. The 600mm trigger exists because that is the height at which a fall starts to matter structurally and from a safety standpoint — guardrails, stair dimensions, and structural requirements all kick in at this height.

In practice, this means the vast majority of decks in the GTA require a permit. If your deck is off the back of a raised bungalow, off a second-storey walkout, or simply elevated enough to require steps, you need a permit. The only decks that typically avoid this threshold are ground-level floating decks on surface piers — and even those need to meet the OBC’s technical requirements.

What a deck permit covers:

• Footing depth and diameter — must extend below the frost line (minimum 4 feet in southern Ontario)
• Beam and joist sizing — must meet OBC span tables for the design load
• Guardrail height and construction — minimum 0.9m for decks under 1.8m above grade, 1.07m above that
• Stair dimensions and handrail requirements
• Setbacks from property lines — Mississauga requires 0.6m side yard and 1.2m rear yard; Burlington allows 0.6m from the rear lot line in most zones; Hamilton has stricter setback enforcement

What this means for the footing work specifically. A permitted deck requires a footing inspection before we pour. The inspector needs to see the open holes — correct depth, correct diameter, clean bottom — before concrete goes in. We can time our work around the inspection, but you need to book the inspection before we arrive. Don’t assume you can call the inspector after we dig and get someone out the same day. That is rarely how it works.

Pergolas: Permit Required in Most Situations

As we covered in our pergola footings post, the permit rules for pergolas are clear:

Attached to the house — any size: Permit required. Full stop.

Freestanding and over 10 square metres (roughly 108 square feet — a 10 x 10 pergola sits right at this threshold): Permit required.

Freestanding and under 10 square metres: May be exempt depending on your municipality — but always confirm locally before you build. Exempt from a permit does not mean exempt from building it correctly.

When a permit is required, footings must extend below the frost line — 4 feet minimum — and a footing inspection is required before the pour. Same sequencing applies as with decks.

Gazebos and Sheds: Same 10 Square Metre Rule

The same threshold that applies to freestanding pergolas generally applies to gazebos and sheds in most GTA municipalities — structures over 10 square metres require a permit. Some municipalities set the threshold lower, so check locally. A large gazebo or a shed over that size that is permanently anchored to the ground will need footings below the frost line and a permit inspection before you pour.

The Timeline Problem Nobody Warns You About

Here is where projects fall apart — not because of the permit rules themselves, but because of how long everything takes when you stack it all up.

Consider a standard GTA deck project in spring:

• You submit your permit application in early April
• Mississauga or Oakville takes 10 to 15 business days — you’re into late April before approval
• Toronto can take 15 to 25 business days in peak season, sometimes stretching to five weeks — you’re in mid-May before you have a permit in hand
• You book us to dig — we call Ontario One Call for locates, which takes 5 to 7 business days
• We dig the holes and you call to book the footing inspection
• The inspector comes out — add another few days for scheduling

By the time the concrete is poured and cured and your deck builder can start framing, it can easily be June or July if you didn’t plan the permit application early.

The practical advice: Apply for your permit in February or March if you want your deck ready for summer. Do not wait until you’re ready to build to start the permitting process. And call us as soon as the permit is approved so we can get locates ordered — those 5 to 7 business days start the moment we call, not the moment you decide you’re ready.

What Happens If You Build Without a Permit

We see this more than we should. A homeowner skips the permit to save time or money, builds the structure, and everything is fine — until it isn’t.

Stop-work orders. If a bylaw officer or inspector identifies unpermitted work in progress, they can issue a stop-work order on the spot. The work stops until the permit is obtained retroactively, which often requires exposing completed work for inspection.

Retroactive permits. Getting a permit after the fact is almost always more expensive and more disruptive than getting one before. Inspectors may require you to expose footings, open framing, or in worst cases, tear down and rebuild sections that can’t be inspected in place.

Real estate problems. When you sell your home, a buyer’s lawyer or home inspector will identify unpermitted structures. This can kill a deal, require price reductions, or force you to obtain a retroactive permit before closing. A deck or pergola that was built without a permit is a liability on your property disclosure statement.

Insurance implications. If an unpermitted structure fails and causes injury or property damage, your homeowner’s insurance may deny the claim on the basis that the structure was not built to code and not inspected.

None of these outcomes are worth the permit fee, which typically runs between $180 and $620 in GTA municipalities depending on the project size and the municipality.

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