Systems through time
Roofing and drainage in older Canadian homes
How did roofing and drainage change in Canadian homes?
Roof coverings on Canadian homes have included wood shingles, asphalt shingles, metal, clay or concrete tile and low-slope membranes. Almost every home older than a few decades has been re-roofed at least once, so the meaningful questions are about the current covering, its installation documentation, ventilation and how water leaves the roof.
What this means
Era suggests the original covering and roof geometry, which can matter for heritage properties and for understanding layered coverings.
What it does not mean
It says nothing about the current roof's age or condition, which must be established by documentation and inspection.
How to verify
- Ask the seller for the roofing invoice, warranty and installation date
- Confirm whether old coverings were removed or roofed over
- Check attic ventilation and any evidence of past leaks
- Review flashing, valleys and drainage discharge locations
Roofing and drainage by construction era
Swipe sideways to compare columns
| Era | Common at the time | Verify today |
|---|---|---|
| Before 1920 | Wood shingles, slate or metal depending on region | Heritage constraints on replacement materials |
| 1920–1939 | Asphalt shingles becoming common | How many layers exist on the roof deck |
| 1940–1959 | Asphalt shingles standard | Ventilation added during later re-roofing |
| 1960–1969 | Asphalt shingles; low-slope additions | Membrane condition on any low-slope area |
| 1970–1979 | Asphalt shingles with ridge and soffit venting | Whether soffit vents are blocked by insulation |
| 1980–1989 | Improved underlayment and ice-dam protection | Ice-damming history in the specific location |
| 1990–1999 | Longer-life shingle products | Documentation for the most recent replacement |
Who can assess this
- Roofing contractor
- Home inspector
- Building envelope consultant for low-slope assemblies
Evidence note
- Sources
- Jurisdiction
- Canada (federal); Canada (model code)
- Applies to
- Roofing and drainage in Canadian residential buildings built roughly 1900–1999
- Last reviewed
- 2026-08
- Limitations
- Describes general Canadian practice by era. Requirements are set provincially and this page does not describe any specific property.
- What you should verify
- Permit and inspection history, service records, and assessment by the appropriate licensed trade.