CHAPTER 9 — G90 Galvanized Steel & Modern Interlocking Metal Roofing
From the 1980s to today, Canada saw the rise of modern steel roofing systems — especially G90 galvanized steel with interlocking panel technology. These advanced designs solved many long-standing problems of asphalt, wood, and earlier metal roofs, offering unmatched durability, snow-shedding performance, and long-term value for Canadian homeowners.
Why G90 Steel Became a Canadian Standard
- Heavy zinc protection: G90 indicates 0.90 oz of zinc per sq. ft., providing exceptional rust resistance.
- Engineered for harsh climates: Steel roofing remains stable in extreme cold, wind storms, and heavy snowfall.
- 50+ year lifespan: Far exceeding asphalt shingles that last 10–18 years in Canada.
- Lightweight but strong: Reduces stress on roof decking and structure.
Interlocking Panel Systems
The introduction of 4-way interlocking steel shingles dramatically improved wind resistance and weather performance. Panels lock together on all sides, preventing uplift, moisture entry, and freeze-thaw damage common with traditional roofing.
SMP & PVDF Coatings
Modern steel shingles use high-performance coatings such as SMP (Silicone-Modified Polyester) or PVDF to resist UV fading, corrosion, and surface breakdown. These coatings also increase reflectivity, improving energy efficiency in hot and cold seasons.
Performance in Canadian Snow Belts
- Snow shedding: Steel naturally releases snow, reducing structural load.
- No water absorption: Prevents the weight gain common in saturated asphalt shingles.
- Eliminates ice-dam risk: Smooth surfaces and proper ventilation reduce melt-freeze cycles.
Impact on Modern Roofing
By the early 2000s, Canadian homeowners began shifting toward metal roofing for longevity, energy efficiency, fire resistance, and reduced maintenance. Brands offering engineered interlocking systems — including G90 steel shingles — became a premium roofing choice across Ontario and nationwide.
This chapter is part of the ROOFNOW™ Canadian Roofing History Archive.