To install asphalt shingles properly, especially in the rainy climate of British Columbia, a professional and systematic approach is required. The process involves the following technical steps:

Preparation and Materials First, a thorough site assessment is conducted to evaluate the roof pitch and structural integrity. Any rot or weak spots must be repaired, and the surface must be clean and dry. Essential materials typically include high-quality asphalt shingles (often algae-resistant for the Pacific Northwest), fiberglass-based underlayment for waterproofing, galvanized nails, and ice and water shields for vulnerable areas.

Installation Steps

1. Starter Course: Apply adhesive-backed starter strips along the eaves to seal against wind-driven rain.
2. First Row: Lay the first row with a five-inch overlap. Use four galvanized nails per shingle, positioned 1-2 inches from the edges to increase wind resistance.
3. Field Laying: Progress up the roof by staggering joints. This prevents water infiltration during heavy downpours.
4. Flashing: Install metal flashing at valleys and chimneys, sealing them with roofing cement.
5. Ridge Capping: Cut shingles into pieces to cover the ridge, securing them with nails for full coverage.

Post-Installation After the shingles are laid, conduct a comprehensive inspection to verify alignment and sealing. It is also critical to check that soffit and ridge vents provide adequate airflow to prevent moisture buildup.