The message from a Mississauga homeowner was admirably short: "The stove wall is clicking again." The hood was switched off. So was the stove. By the time we arrived, the wind had stopped and the kitchen had decided to behave. A thirty-second phone recording was more useful than our first ten minutes of listening.
Listen for the pattern
A backdraft damper is a flap intended to let exhaust leave and limit air coming back through the duct. Some installations have a damper at the hood, at the exterior termination, or in another specified position. The route and the product instructions determine the arrangement.
FAMCO's damper guidance identifies wind-driven opening and closing as a possible cause of banging near kitchen or bathroom exhausts. That gives you a sensible place to investigate, not a reason to order the first replacement flap online.
| When it happens | Useful next observation |
|---|---|
| With gusts, even with the fan off | Record the wind and the sound; inspect the exterior cap from a safe ground position. |
| Only with the fan running | Note which speeds cause it; a loose filter, vibration or fan fault needs a different check. |
| With poor extraction as well | Ask the installer to check the whole exhaust path, not just quiet the noise. |
A quiet flap still has to open
Do not tape it shut, wedge it open, glue household foam into the air path or attach a coin to make it heavier. A clever-looking fix can stop the flap opening properly or leave a permanent draught. Replacement parts need to suit the hood, duct and exterior location.
Have the installer check the cap's condition and orientation, free movement, unwanted obstructions and any conflicting dampers in the system. Roof or high-wall inspection belongs with someone equipped for that access. You can supply the recording without balancing on the barbecue.
Fix the detail you actually find
At that house, the exterior flap was catching at one edge. We arranged a compatible replacement and checked it with the hood running before calling the job done. There was no reason to replace the kitchen's perfectly good extractor. The homeowner sent a second recording that evening. Mostly a dishwasher, and a very pleased silence from the wall.
For an older installation, keep the duct-size check nearby. If several fans or doors behave oddly together, include the home's make-up air arrangement in the review. A noise complaint can be a small job; it should still finish with ventilation that works.
Before touching an unfamiliar outlet outdoors, use our guide to sidewall vents and pipes. A kitchen exhaust, dryer outlet and combustion vent are different things.