Roofing in Ontario is governed by Part 9 of the Ontario Building Code (OBC), which covers housing and small buildings. Part 9 sets minimum standards for roofing materials, ice and water protection, attic ventilation, and wind uplift resistance. These requirements are not optional — they apply to all new construction and most full replacements. Understanding them helps you evaluate whether a contractor's proposed scope of work actually meets code.
Ice and Water Shield Requirements
The OBC requires self-adhering waterproofing membrane (ice and water shield) at all eaves, extending a minimum of 900 mm (approximately 36 inches) measured from the interior face of the exterior wall inward — not from the drip edge. On a typical overhang, this means ice and water shield covers the eave and extends partway up the roof slope past the wall line.
The intent is to protect against water backup caused by ice dams. However, many experienced Renfrew County contractors extend ice and water shield coverage well beyond the OBC minimum, given the Ottawa Valley's significant snowfall and ice dam history. Common expanded coverage in this region includes:
- Ice and water shield covering the full eave overhang plus an additional course up the slope
- Ice and water shield in all valleys (required by code as part of valley protection)
- Ice and water shield around all penetrations (chimneys, vents, skylights)
- Full coverage on lower-slope sections where snow tends to accumulate
The additional material cost for extended ice and water shield coverage is modest relative to the water damage it prevents. When reviewing quotes, ask specifically how much ice and water shield each contractor plans to install and where.
Attic Ventilation Requirements
Adequate attic ventilation is essential for preventing ice dams, moisture buildup, and summer heat gain. The OBC sets minimum ventilation ratios under Part 9:
| Condition | Required Ventilation Ratio |
|---|---|
| Without vapour barrier (older construction) | 1:150 — 1 sq ft vent area per 150 sq ft ceiling area |
| With vapour barrier (modern construction) | 1:300 — 1 sq ft vent area per 300 sq ft ceiling area |
Ventilation must be distributed between the low (soffit) and high (ridge or gable) positions. Intake at the soffits draws cool air; exhaust at the ridge allows warm, moist air to exit. A balanced system keeps the roof deck temperature consistent across all seasons — reducing ice dam formation in winter and extending shingle lifespan in summer.
When replacing a roof, the contractor should assess the existing ventilation and confirm it meets the OBC ratio. Deficient ventilation is a common finding, particularly in homes with blocked or missing soffit vents under old eavestroughs.
Wind Uplift Resistance
OBC Part 9 includes requirements for wind uplift resistance — the ability of the roofing system to remain attached under the negative pressure created by wind passing over the roof surface. Shingle nailing patterns, the number of nails per shingle, and the use of starter strips at eaves all affect wind uplift performance.
The Ottawa Valley is subject to periodic high-wind events. Architectural shingles with a 110 mph or higher wind resistance rating are the standard choice in this region. The manufacturer's rated wind resistance is typically only achieved when the shingles are installed with the correct nailing pattern — confirm your contractor follows the manufacturer's installation specifications, as deviation can void the product warranty.
Building Permits for Roofing in Renfrew County
Most Renfrew County municipalities require a building permit for a full roof replacement. Patch repairs and minor maintenance work typically do not require permits, but a complete tear-off and re-roof is considered a substantial roofing project and generally triggers the permit requirement under local bylaws.
Key points about permits for roofing:
- The contractor should pull the permit, not the homeowner. A contractor who pushes responsibility for the permit onto the homeowner is a red flag — it often means they intend to avoid the associated inspection.
- Permit fees in Renfrew County municipalities typically range from $150–$600 depending on the municipality and project value. This cost should be included in the contractor's quote.
- Inspection: A permit ensures a building inspector reviews the work — primarily ventilation and ice and water shield placement — before or after completion. This protects you as the homeowner.
- Insurance implications: Unpermitted roofing work can create complications with home insurance claims if a subsequent roof-related water intrusion occurs.
See our guide to Renfrew County building permits for municipality-specific information on how to apply and what to expect.
Contractor Licensing and WSIB
There is no provincial trade licence specifically required for roofing contractors in Ontario, unlike electricians or plumbers. This means homeowners cannot rely on a licence check to verify qualifications — making other verification steps (WSIB, references, portfolio, written contract) more important.
All contractors working on residential properties in Ontario must carry WSIB (Workplace Safety and Insurance Board) coverage. Roofing is a high-fall-risk trade — WSIB coverage is non-negotiable. Verify your contractor's status at wsib.ca before signing any contract. See our main roofing guide for a full overview of roofing services in the region.