How Long Does a Building Permit Last? A Guide for Ontario Homeowners

Wondering how long a building permit lasts in Ontario? Learn permit validity timelines, expiry rules, extension options, and how to keep your project on track.

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How Long Does a Building Permit Last? A Guide for Ontario Homeowners
How Long Does a Building Permit Last? A Guide for Ontario Homeowners

People often get burned by permit expiration even though they get proper permits beforehand, being organized and smart about home renovations. But oftentimes, they are unable to get the renovation started quickly as life gets in the way and by the time they are ready to start building, their permit has turned into expensive toilet paper.

A lot of people mistake permits for driver's licenses, get them once, and use them whenever. But this is not the case. We often get calls from panicked homeowners who just discovered their permits expired while they were shopping for contractors or waiting for their tax refund to clear.

Here's the deal: building permits in Ontario come with hidden timers, and if you don't know the rules, you'll learn them the hard way.

Construction workers looking at building permits.
Construction Workers Looking at Building Permit.

How Long Does a Building Permit Last?

You've got six months from the day they issue your permit to actually start swinging hammers. Not planning to start. Not thinking about starting. Actually breaking ground and doing the work your permit describes.

This isn't some loose guideline either. Municipal building departments track this stuff religiously. A lot of times the inspectors show up on day 181 asking why there's no construction activity.

Now, once you start working, things get a bit more flexible. Most places let you keep going as long as you don't stop for more than six months. But ‘stop' doesn't mean taking weekends off or dealing with a two-week material delay. We're talking about major gaps where nothing's happening on-site.

Let's assume you start a project in May, get done with demolition and rough framing, and then decide to take a short break to deal with some personal issues. Your short break turns into eight months and when you try to continue, the city informs you your permit is as dead as a doornail.

The Reality of Permit Expiration

Here's what really happens when permits expire, and it's uglier than most people realize.

First off, you can't just keep working and hope nobody notices. Any work done after permit expiration is considered illegal construction. I've seen stop-work orders slapped on projects that were 90% complete because somebody ignored expiration dates.

Getting new permits for half-finished work is not easy and requires complex paperwork. You need drawings showing what's already done, engineering reports proving the existing work is safe, and often you have to bring everything up to whatever building codes are current now, not what they were when you started.

Toronto's particularly strict about this stuff. If you don't start construction within 18 months, they'll send you a formal "notice of intention to revoke" your permit. Once that happens, you're starting completely over and will need a new permit to renovate your house.

What Does Starting Construction Actually Means?

This is where people get tripped up constantly. You'd think digging a hole or ordering lumber would count as starting construction but that's not it.

The city wants to see actual construction activity related to your specific permit. If your permit is for a kitchen renovation, tearing down walls in the basement doesn't count. If you're permitted for an addition, excavating the area might count, but only if you're actually pouring footings soon.

You have to be careful about not just spending three weeks in site preparation, clearing brush, moving garden shed, or digging test holes for drainage. None of this will count if your permit was for a deck addition and deck construction hadn't actually begun. His permit expired while he was preparing the site.

The smart move is to call your building department before you start and ask exactly what activities they consider commencement of construction for your specific permit. Different inspectors sometimes have different opinions, so get it in writing if possible.

Wooden structure for a home addition project under construction.
Wooden Structure for a Home Addition Project.

How Do Building Permits Work in Ontario?

There’s no short answer to how long a building permit lasts in Ontario. Every city in Ontario has special laws and their own interpretations of permit validity.

Toronto has an 18-month notice but they also track continuous progress differently than smaller cities. Miss a required inspection by more than six months and they might consider your permit abandoned even if you're actively working.

Mississauga has its own rules about what constitutes continuous work. Some contractors have to photograph their job sites monthly just to prove work is progressing because Mississauga's building department has challenged permit validity based on aerial photography showing no visible progress.

In some places, the interior renovations don't count as visible progress for permit validity purposes. You need exterior signs of construction activity for them to consider work ongoing. Never mind that you might be doing months of electrical and plumbing work inside.

The smaller municipalities are sometimes worse because they don't have consistent policies.

Extending Building Permits

Most places let you extend permits but it's better to ask before they expire.

Extension applications usually require details about why you couldn't start on time. Weather delays are accepted, especially if you can document specific weather events that prevented construction. Contractor problems might work if you can prove your original contractor bailed or got injured.

Family emergencies, financing issues, or changing your mind about the design doesn't cut it with building departments.

It's best to ask for extensions at least 30 days before expiration. Some municipalities want 60 days' notice. Nobody appreciates last-minute extension requests and inspectors get serious about them.

Extension fees vary wildly. Some places charge nothing, while others want half the original permit fee. Toronto charges based on the complexity of your project and how many extensions you've already requested.

Do Permits Expire in Ontario?

Knowing how long a building permit lasts and staying on top of timelines is key to smooth home renovations. Here's a fresh complication that's making the process more complex. Ontario switched to the 2024 Building Code in January, and as of April, all new applications get reviewed under the new rules.

This creates timing nightmares for anyone whose permits expire this year. If you get permits under the old code but they expire and you need to reapply, your new application gets reviewed under 2024 standards. Sometimes that means redesigning parts of your project or adding requirements that didn't exist before.

Some people are scrambling to start construction they weren't ready for just to avoid having to redesign under new code requirements. It's created this weird rush where people are starting projects they're not financially ready for because reapplying later would cost more.

Common Mistakes to Avoid

The biggest mistake is treating permits like they're permanent. People get excited about approval, and then assume they can start whenever they feel like it.

Contractor scheduling screws up more permits than anything else. Homeowners get permits approved, then start shopping for contractors. By the time they find someone available and affordable, six months have passed and permits have expired.

Seasonal planning kills a lot of permits too. People apply for permits in winter for summer construction, not thinking about the six-month expiration window. When spring arrives and contractors are finally available, permits are already dead.

Financing delays are huge permit killers. Getting permit approval feels like progress, so people apply before they've actually secured construction loans or saved enough money. Then they spend months trying to get financing while their permits expire.

Material delays have also gotten worse since COVID. People order custom windows or specialty materials, expecting quick delivery, then discover six-month wait times. Meanwhile, their permits are ticking toward expiration.

Strategies That Work

Construction permit being examined by city hall workers.
Construction Permit Under Examination.

Don't apply for permits until you're genuinely ready to start within 90 days. Yes, permit processing takes time, but it's better to wait an extra month for approval than to get early approval that expires before you're ready.

Have your contractor lined up before applying. Permits shouldn't be part of your contractor shopping process, they should be part of your construction execution process. Keep processing time into your planning. If you think you'll be ready to start in four months, apply for permits in month three.

Keep detailed records of any construction activity. Photos, receipts, inspection records, anything that proves work is progressing. It's best to take weekly progress photos even if progress looks minimal. Stay in touch with your building department. If delays are unavoidable, call them early and explain the situation. Some inspectors are reasonable if you communicate proactively.

Respect the expiration dates, but plan around them strategically. And if you're working with contractors who don't understand permit expiration rules, find different contractors. 

Want help navigating permits, inspections, and renewal deadlines? We manage everything from drawing submissions to final sign-offs. Contact us today to book a consultation. Remember, building permits might expire but good planning and realistic scheduling can keep your project on track without disasters.

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