If you are planning a renovation, addition, or new construction project in Ontario, understanding building permits is essential. Whether the project is residential, commercial, or industrial, permits ensure your work complies with the Ontario Building Code and local municipal regulations.

For many property owners, the permit process can feel confusing or overwhelming, especially if it is your first time dealing with it. This guide breaks down what a building permit is, when it is required, when it is not, and how to approach the process with confidence.

What Is a Building Permit?

A building permit is an official approval issued by your local municipality. It confirms that your construction plans meet the requirements of the Ontario Building Code, local zoning bylaws, and applicable safety standards.

Before work begins, the municipality reviews drawings, structural details, and system layouts. Once approved, the permit allows you to legally proceed with construction, renovation, demolition, or a change in building use. Inspections are typically required at different stages of the project to ensure compliance throughout construction.

Do You Need a Building Permit in Ontario?

Not every project requires a permit, but many do. Requirements can vary slightly between cities and regions across Ontario, which is why it is important to verify the rules before starting any work.

In general, permits are required when construction affects structure, safety, building systems, or the intended use of a space.

When a Building Permit Is Required

You will typically need a building permit in Ontario if your project includes any of the following:

New Construction and Additions

• Constructing a new building

• Adding a second or third storey

• Attached garages or carports

• Sunrooms, solariums, porches, or decks

• Enclosing existing porches, patios, or decks

Structural or Material Changes

• Adding or removing interior or exterior walls

• Changing room sizes or building layout

• Creating new window or door openings

• Enlarging or relocating existing windows or doors

Accessory Structures

• Sheds 15 square metres (161 sq ft) or larger

• Detached garages, workshops, carports

• Pool houses, cabanas, or similar structures over 10 square metres

Basement Work

• Structural modifications

• New plumbing or HVAC installations

• Excavation or foundation work

• Underpinning

• Basement entrances

• Adding a second unit or secondary suite

Mechanical, Electrical, and Safety Systems

• Installing or modifying heating or plumbing systems

• Chimneys or fireplaces

• Wood-burning stoves

• Backwater valves

• Backflow prevention devices

Energy and Environmental Systems

• Green roofs

• Rooftop stormwater retention systems

• Solar collector or solar hot water systems

• Wind turbine support structures over 3kW

Other Situations

• Decks more than 60 cm (24 inches) above ground

• Retaining walls over 1 metre in height near public areas

• Large tents meeting size or proximity conditions

• Partial or full demolition of a building

• Change of building use, even if no construction is planned

When a Building Permit Is Not Required

Some minor projects may not require a building permit, provided they meet zoning and safety requirements.

Common examples include:

Exterior and Structural Items

• Uncovered decks less than 60 cm above grade that are not part of a required exit

• Retaining walls under 1 metre high on private property

• Replacing roofing materials without structural changes

Interior Work

• Installing cabinetry or millwork

• Replacing plumbing fixtures

• Finishing a basement without structural changes, new plumbing, or additional dwelling units

• Basement waterproofing repairs

Windows, Doors, and Insulation

• Replacing windows or doors with no change in size or location

• Adding or replacing insulation

• Installing skylights in small residential buildings without major structural changes

Mechanical Systems

• Replacing furnaces or boilers in houses

• Installing air conditioning units, gas fireplaces, air cleaners, humidifiers, or hot water tanks

• Installing sump pumps

Accessory Structures and Temporary Installations

• Small sheds under 15 square metres that meet exemption requirements

• Seasonal plastic-covered structures installed and removed within approved dates

Even when a permit is not required, zoning bylaws and other regulations still apply.

Navigating the Permit Process in Ontario

Applying for a building permit involves preparing accurate drawings, understanding local bylaws, and coordinating with municipal reviewers and inspectors. Mistakes or missing information can lead to delays or rejections.

Working with an experienced construction team early helps ensure your project scope, design, and documentation are aligned with municipal requirements from the start.

How Makens Supports Permit Coordination Across Ontario

Makens works with property owners, developers, and businesses across Ontario to help streamline the permit process. Our team understands how permit requirements impact timelines, budgets, and construction sequencing.

We support projects by:

• Coordinating design and permit-ready documentation

• Aligning construction plans with Ontario Building Code requirements

• Managing inspections and compliance during construction

• Reducing delays caused by incomplete or incorrect submissions

Final Thoughts

Building permits are not just a legal requirement. They protect your investment, ensure safety, and help prevent costly issues down the road. Knowing when a permit is required and planning for it early can save time, money, and frustration.

If you are planning a construction or renovation project anywhere in Ontario and have questions about permits or compliance, Makens is here to help you move forward with clarity and confidence.

Contact Makens to discuss your project and get started the right way.