Our 1991 Whitby home had original architectural shingles — 27 years old when we finally replaced them in 2024. The inspector had been noting “approaching end of life” for 4 years. We held off too long — sharing what we found and what it cost.
Assessment:
Inspector: extensive granule loss, 4 shingles with cracks, visible cupping in 2 valleys, and two areas of soft deck (suspected rot under the sheathing). We had been patching a small kitchen leak for 2 years. The roof was overdue.
The tear-off discovery:
When the crew tore off, they found:
- 6 sheets of rotted OSB deck sheathing in the 2 valleys
- The kitchen leak was from a failed valley flashing, not a shingle issue — it had been leaking for longer than we knew
- The garage roof was also included (same age, we added it to the quote)
Quotes received (house roof + garage, approx 1,800 sq ft total):
- Quote A: $14,200 (IKO Cambridge HP, standard ventilation)
- Quote B: $12,800 (Owens Corning Duration, upgrade ventilation from slant to ridge)
- Quote C: $16,400 (Certainteed Landmark PRO, full ridge ventilation, ice and water shield valleys)
We went with Quote B at $12,800. The contractor also found the deck rot on Quote B — included the sheathing replacement in the contract.
Extra cost for rot repair:
- 6 sheets of 5/8-inch OSB deck: $340 supply + $280 labour = $620
Final cost: $13,420
What I learned:
The kitchen leak was the most expensive part — not because of roof cost, but because we had water damage inside the kitchen ceiling for 2+ years that we hadn’t identified. Add $3,200 in interior repair on top of the roof.
Don’t patch a leak for 2 years. Get a roofing company to identify the source.