Creosote takes on a shiny, potato chip like crispy texture when it becomes dangerous.
Greater Vancouver bylaws are to inspect or clean every year. Because fireplaces can be different there isn’t a simple rule of thumb. Most common practices are to clean before the burning season and every fifty fires.
The Scratch Test
A simple DIY scratch test can determine the level of dangerous creosote buildup on a common brick fireplace. Using chimney tools like a hot poker or a small shovel and a flashlight you can scratch the back of the smoke shelf or flue to see the sticky tar and creosote along the walls.
A 1/4 inch thick of creosote is deemed a fire hazard and should not be used until it can be cleaned. If the chimney flue shows a thickness of 1/8 inch you should consider making an appointment soon.
Here is a drawing to give you a basic idea about a brick fireplace.Warning signs:
1) Smoke or bird intrusions.
2) Bad smells, flies or maggots.
3) Water stains or rusted steel chimney flues.
4) Broken dampers, loose damper arms or pins.
5) Damper gaps leading to expensive heat loss and cold drafts.
6) Large cracks or holes in the firebox floor or along the walls.
7) You don't use a grate to hold the wood off of the firebox floor.
8) You lack a stone fireguard, metal screen, glass doors or a chimney cap.
9) It has been more than fifty fires since the last clean.
We remove birds and nests.
Prevent fires with inspections and cleans.
We install caps, pest screens and spikes.