If you are a homeowner in London preparing for a real estate transaction or an insurance renewal, you already know you need a WETT inspector. However, many homeowners fall into a highly expensive trap by booking their inspection without first ensuring their chimney is professionally cleaned.
At London WETT Connect, we see it constantly: a homeowner pays $300 for an inspection, only to have the inspector stop five minutes into the appointment because the system is too dirty to evaluate. To ensure a successful pass, you must sequence these services correctly.
The "Failure to Inspect" Trap: Auditor vs. Cleaner
The first thing to understand is that a WETT inspector and a chimney sweep perform two entirely different functions. A WETT inspector is essentially a compliance auditor.
Their job is to document facts, take exact measurements, and evaluate whether your wood-burning system meets the strict clearances of the National Fire Code of Canada. They are not there to scrub your flue or get covered in soot.
If you book an inspection for a system that has been used all winter without a cleaning, you are essentially asking an auditor to check a financial ledger where half the pages are covered in black ink blots.
The 3mm Rule: The Inspector’s Ethical Mandate
The National Fire Code is unambiguous: a buildup of more than 3 mm (1/8 inch) of creosote on the walls of a chimney represents an active fire hazard.
When a professional arrives at your home, their first step is a visual assessment of the flue. If they encounter a layer of creosote exceeding that 3mm threshold, they cannot legally proceed with a standard inspection report that verifies the system as "safe." Because an inspection report can only include what is visible, a flue coated in soot renders the inspection impossible.
Stop Paying for Double Visits
Answer 3 quick questions to evaluate your system's history and see if you need to book a sweep before your inspector arrives.
What Soot is Hiding: The Danger of the Unseen
The primary reason you need a chimney sweep first is that soot and creosote are masters of disguise. A heavy layer of soot can easily hide severe structural defects, including:
- Cracked Flue Tiles: In masonry chimneys, clay liners develop splits due to thermal shock.
- Perforated Stainless Steel Liners: Acidic creosote can eat tiny holes through metal liners, allowing carbon monoxide to leak into your home.
- Damaged Baffles and Firebricks: Soot piles up on internal components, hiding cracks or warping that indicate the appliance is failing.
By hiring a sweep first, you clear the "diagnostic canvas," allowing the inspector to verify the actual structural integrity of the venting system.
Strategic Sequencing: Save Your Money
If you book an inspector and they cannot complete the job because the flue is dirty, you will likely still be charged for the service call. You will then have to pay for a chimney sweep, and then pay the inspector to come back a second time.
To avoid paying for two separate visits, you must sequence the services correctly:
- Step 1 (The Sweep): Hire a professional to clean the venting, chimney system, and firebox.
- Step 2 (The Inspection): Once the system is clean, the inspector can perform a Level 1 or Level 2 SITE® inspection with a clear view of all components.
Don't gamble with compliance. Stop guessing and start preparing. Use our Free London WETT Triage Tool to evaluate your system's maintenance history. Our tool will tell you exactly what sequencing your specific system requires.