Ontario Roofing Regulations

Governing Law: The Ontario Building Code

Residential roofing in Ontario is governed by the Ontario Building Code (O. Reg. 332/12), which is a regulation under the Building Code Act, 1992. The specific provisions for roofing are found in Part 9 — Housing and Small Buildings, Section 9.26 — Roofing. This section sets out minimum requirements for roof covering materials, underlayment, flashing, ice and water shield, ventilation, and installation methods.

The Ontario Building Code is available online at: https://www.ontario.ca/laws/regulation/120332

Part 9 applies to buildings of three storeys or less with a building area not exceeding 600 square metres, which covers the vast majority of residential homes in Renfrew County. The Code is updated periodically, and homeowners should verify they are referencing the current version.

When Is a Building Permit Required?

Permit requirements for roofing vary by municipality in Renfrew County. The general rules are:

• Full re-roofing (tear-off and replacement): A building permit is required in most municipalities, including Pembroke, Petawawa, Renfrew, Arnprior, and Deep River. The permit fee typically ranges from $100 to $400.
• Repairs: Minor repairs (replacing a few shingles, fixing flashing) generally do not require a permit.
• New construction: Any new roof on a new building requires a full building permit as part of the overall construction permit.
• Structural changes: If the roof structure is being modified (e.g., adding dormers, changing pitch), a permit is always required regardless of the municipality.

The permit process typically involves submitting plans or a description of the work, paying a fee, and scheduling at least one inspection during the installation. The inspection verifies that underlayment, ice and water shield, and flashing meet Code requirements before shingles are applied.

Contractor Credential Requirements

Ontario does not have a provincial licensing system specifically for roofing contractors (unlike wells, electricians, or HVAC technicians). However, several requirements apply:

• WSIB coverage: All roofing contractors in Ontario must have Workplace Safety and Insurance Board coverage. You should request a WSIB clearance certificate and verify it online through the WSIB clearance database.
• Liability insurance: While not legally required by the province, reputable contractors carry minimum $2 million liability insurance. This protects both the contractor and the homeowner in case of accidental damage.
• Business registration: Contractors operating under a business name must register with the Ontario Business Registry. A sole proprietor may operate under their legal name without registration.
• Municipal business licences: Some municipalities in Renfrew County require contractors to hold a local business licence. Check with the municipality where the work is taking place.

See the hiring guide for a detailed step-by-step process for verifying contractor credentials in Renfrew County.

Ice and Water Shield Requirements

The Ontario Building Code requires ice and water shield membrane on roofs with slopes of 1:3 or steeper in specific locations:

• At eaves: Minimum 900 mm measured from the interior wall line (not from the eave edge). On a typical wall with 2x6 top plates and 12-inch overhang, this means the membrane extends approximately 1,200–1,500 mm from the eave edge.
• In valleys: Full coverage of the valley, extending a minimum of 300 mm on each side of the valley centre line.
• Around penetrations: Flashing boots for vents, pipes, and other penetrations should be installed over ice and water shield where present.
• At obstructions: Dormers, skylights, chimneys, and roof-to-wall intersections require ice and water shield integration with flashing.

Many Renfrew County homeowners choose to extend ice and water shield coverage across the entire roof deck rather than limiting it to the minimum Code requirements. The additional cost (typically $800–$2,000 for a standard home) provides comprehensive protection against ice dam damage and wind-driven rain. Given the region’s snowfall, this is a widely recommended upgrade.

Ventilation Requirements

The Ontario Building Code requires attic ventilation to prevent moisture accumulation and reduce ice dam formation:

• Minimum ratio: 1:300 of vent area to insulated ceiling area (e.g., a 1,500 sq ft ceiling needs at least 5 sq ft of total vent area).
• Distribution: 50% of vent area should be intake (soffit or eave vents) and 50% exhaust (ridge vent, roof vents, or gable vents).
• Higher ratios: Some Renfrew County municipalities may require 1:150 for certain roof configurations, particularly where the roof slope is less than 1:3 or where vaulted ceilings limit attic space.
• Obstructions: Insulation must not block soffit vents. Baffles or chutes should be installed to maintain airflow from the soffit into the attic space.

Municipal Permit Requirements by Area

Other Code Requirements

Maximum Shingle Layers

The Ontario Building Code permits a maximum of two layers of asphalt shingles on a residential roof. The second layer must not exceed the first in weight. Many Renfrew County contractors recommend full tear-off regardless, as leaving the old layer conceals deck condition and reduces new shingle lifespan.

Minimum Roof Slope

Asphalt shingles require a minimum roof slope of 1:6. Low-slope or flat roofs require different materials such as modified bitumen, EPDM, or built-up roofing. These are less common on residential homes in Renfrew County but may be found on additions, porches, or garages.

Flashing Requirements

The Code requires corrosion-resistant metal flashing at all roof-wall intersections, around chimneys, at skylight perimeters, and at roof penetrations. Step flashing must be integrated with wall cladding. Counter flashing must be embedded in masonry joints for chimneys. Drip edge is required at eaves and rakes.