Overview
- For most homes in Ottawa, replacing asphalt shingles with new asphalt shingles does not need a building permit.
- A permit becomes necessary when the work changes the roof’s structure, such as replacing trusses, altering the roofline, adding a dormer or cutting in a new skylight.
- Homes in a Heritage Conservation District or with a heritage designation follow separate rules and may need a Heritage Alteration Permit.
- No permit does not mean no rules. The Ontario Building Code still applies to the work, including eave protection and attic ventilation.
- Switching to a heavier or different roofing material is worth confirming with the City before you sign a contract.
- A good roofing contractor will check the permit question for your address before work begins.
Few things slow down a home project like the word “permit.” Homeowners picture forms, fees, inspections and weeks of waiting, so it is no surprise that one of the first questions we hear before a roof replacement is whether the City needs to get involved.
The short answer is that most standard roof replacements in Ottawa do not need a building permit. But there are real exceptions, and getting them wrong can mean stop-work orders, extra costs and headaches when you sell the house.
Here is a plain-language guide to when you need a permit for a roof replacement in Ottawa, when you do not, and what rules still apply either way.
When You Do Not Need a Permit
The City of Ottawa lists installing asphalt shingles on a roof among the projects that do not need a building permit. In practice, that covers the most common job: tearing off the old shingles and putting new ones on, with no changes to the structure underneath.
The reasoning is simple. Replacing the roof covering is treated as maintenance, not construction. Your trusses, rafters and roof deck stay exactly as they were, so the City has nothing structural to review.
When You Do Need a Permit
The line gets crossed when the project changes the structure of the roof. Under Ontario’s Building Code Act, a permit is needed for construction or a material alteration of a building, and several roofing projects fall into that category.
|
What you are doing |
Permit needed? |
| Replacing asphalt shingles with new asphalt shingles, no structural changes | Generally no |
| Patching isolated spots of damaged plywood or OSB | Generally no, treated as maintenance |
| Replacing damaged trusses or rafters, or large areas of structural sheathing | Yes, speak to the City first |
| Changing the roof’s shape or pitch | Yes |
| Adding a dormer | Yes |
| Cutting in a new skylight where there was none | Yes |
| Switching to a much heavier material, such as slate or concrete tile | Confirm with the City, a structural review may be needed |
| Changing exterior materials or colors on a heritage property | Heritage permit required |
Roofers often discover rotten wood only after the old shingles come off. If the repairs turn out to be structural, the job can shift from permit-exempt to permit-required in the middle of the project, which is why an early roof inspection in Ottawa and a clear conversation with your contractor help.
Heritage Properties Follow Different Rules
If your home is individually designated under the Ontario Heritage Act, or sits inside a Heritage Conservation District, the standard exemption does not apply to changes that affect how the building looks. Ottawa has several of these districts, including Rockcliffe Park, New Edinburgh, Sandy Hill and Centertown.
In those areas, changing roofing materials, profiles or colors generally requires a Heritage Alteration Permit before work starts. Moving from slate, copper or cedar shake to modern asphalt shingles may not be approved if it does not fit the district’s guidelines. Heritage approvals can take several weeks, so apply early and do not book a crew until you have the answer.
Not sure whether your address is in a protected area? Ask the City, or ask your contractor to check before they quote the job.
No Permit Does Not Mean No Rules
This is the part many homeowners miss. A roof replacement that does not need a permit still has to meet the Ontario Building Code. The exemption only means the City does not review or inspect the job. The work itself must still be done properly.
For asphalt shingle roofing in Ottawa, the Code’s roofing and ventilation sections cover several things your contractor should be doing on every job:
- Eave protection. A waterproof membrane, commonly called ice and water shield, must run from the roof edge at least 900 mm (36 inches) up the slope and reach at least 300 mm (12 inches) inside the inner face of the exterior wall. It exists because ice dams are a fact of life here.
- Proper flashing. Valleys and chimneys need flashing details that keep snow and meltwater from collecting where they should not.
- Attic ventilation. The Code sets a minimum ratio of vent area to ceiling area, generally 1 square foot of vent for every 300 square feet of insulated ceiling on a conventional sloped roof. Our post on how a ridge vent extends roof life explains why airflow matters.
- Sound decking. Any replacement sheathing has to meet Code requirements for thickness and fastening.
If a contractor says “no permit needed, so we can skip the details,” that is a red flag. We cover the latest changes in our guide to the 2025 Ontario Building Code updates, and the Province publishes the full text of Ontario Regulation 332/12.
What Happens If You Need a Permit
If your project does cross into structural work, the process is manageable when you plan for it:
- Confirm the scope. Work out with your contractor whether the project involves structural changes, a new skylight or dormer, or a heritage property.
- Prepare drawings if needed. Projects that alter the roof structure usually need scaled drawings from a qualified designer, showing existing conditions and the proposed framing.
- Apply to the City. Submit the application and drawings to Building Code Services. The City’s page on projects that do not need a building permit is a good place to start, and staff can tell you where your project falls.
- Pay the fees. Permit fees are based on the value of the work. The City publishes its current fee schedule online.
- Wait for approval before starting. Do not begin the structural work until the permit is issued, and keep it posted at the site.
- Book the inspections. Structural work usually requires an inspection before the framing is covered up, and a final inspection when the job is finished.
Starting structural work without a required permit can lead to stop-work orders, additional fees and problems when you sell or make an insurance claim, so it is not worth the risk.
Questions to Ask Your Contractor
Before you sign, ask:
- Does my project need a permit, and who is responsible for getting it?
- What happens if you find rotten decking or damaged framing once the old roof is off?
- Is my home in a Heritage Conservation District or designated?
- How will the work meet Ontario Building Code requirements for eave protection and ventilation?
A contractor who answers these clearly is probably one who has done it before. Our guide on how to check a roofing contractor in Ottawa has more questions worth asking.
Frequently Asked Questions
Do I need a permit if I replace some of the plywood under my shingles?
Replacing isolated damaged spots is generally treated as maintenance. Replacing large sections of structural sheathing, or damaged rafters and trusses, is a different matter and may need a permit. If your contractor finds extensive rot, ask them to confirm with the City before work continues.
Do I need a permit to switch to a metal roof?
It depends on the material and the weight it adds to your structure. Metal roofing in Ottawa is a popular upgrade, and our guide to metal vs asphalt roofing covers the pros and cons. The City’s permit exemption names asphalt shingles specifically, so check with Building Code Services before you commit to a different material.
Can I add a skylight during my roof replacement?
Yes, but a new skylight is not a permit-exempt change. Cutting an opening in the roof can involve cutting or reframing structural members, so a permit is generally required. If skylight installation in Ottawa is on your wish list, tell your contractor early so the permit and the roof schedule line up. Our post on fixed skylights for pitched roofs can help you decide.
What happens if I do structural roof work without a permit?
The City can issue a stop-work order, and you may face extra fees to get the permit after the fact. Unpermitted structural work can also create problems when you sell your home or file an insurance claim, so it is better to sort out the permit first.
Summary
For most Ottawa homeowners, replacing asphalt shingles with new asphalt shingles does not require a building permit. A permit comes into play when the work changes the structure, such as replacing trusses, altering the roofline, adding a dormer or cutting in a new skylight. Heritage properties follow their own rules, and a Heritage Alteration Permit may be needed before you change roofing materials or colors.
Even when no permit is required, the Ontario Building Code still applies. Proper eave protection, flashing and attic ventilation are part of every well-done roof, whether or not the City ever visits.
If you are planning a roof replacement and want help sorting out what your home needs, request a free quote or call Taylor Roofing at 613-416-6215. We will look at your roof, explain what is involved and point out anything that could affect permits before work begins.