Chimneys are the most neglected exterior component on most Ontario homes. Here’s what fails, what it costs to fix, and what the WETT process looks like.
Common failure modes and GTA costs (2026):
Mortar joint deterioration:
Freeze-thaw and acid rain destroy mortar joints over 20-40 years. Repointing (remove deteriorated mortar to 25mm, repack with matched mortar): $400-$800/linear metre of scaffold reach. Wrong mortar (harder than brick) causes brick face to spall – match original composition.
Chimney crown:
Cracked crown allows water to run down the outside of the flue liner. Crown repair: $300-$800. Crown replacement: $600-$1,500. Metal rain cap over flue opening: $150-$400 installed.
Flashing:
Step flashing + counter-flashing is correct. Caulk-only flashing from cheap reroofing fails in 5-10 years. Chimney flashing replacement: $600-$1,800.
WETT inspections:
Required by most Ontario insurers for wood-burning appliances:
- Level 1 (visual): $200-$300
- Level 2 (visual + camera flue): $300-$500
- Creosote sweeping: $150-$300
- Stainless liner installation: $2,000-$5,000
Ontario chimney and masonry contractor referrals at home.renovation.reviews