Creosote is the black, tar-like residue that condenses inside your flue as wood smoke cools. Once it builds up past 3mm, it becomes flammable — and a flue fire hits temperatures that will melt a stainless steel liner. Regular cleaning is the cheapest insurance policy your fireplace will ever have.
The rule of thumb
- Light seasonal use (10–15 evenings a winter): sweep once a year, in autumn.
- Regular use (3–5 evenings a week through winter): sweep twice — once at the start of winter, once mid-season.
- Daily use / primary heat source: sweep every 3 months during use.
- Rule: every 1 tonne of wood burned = one sweep due.
Signs you're overdue
The fire is harder to light and doesn't draw properly. There's a strong smoky smell in the room when the door opens. You can see dark staining above the fireplace opening. Any of these means creosote is restricting airflow — book a sweep before your next fire.
What a professional sweep costs
A full flue sweep and inspection runs R750–R1,500 in the Western Cape depending on flue height and access. It takes about an hour, uses no chemicals, and includes checking the door seal, baffle plate and firebox for wear.
DIY vs professional
You can buy a flue brush set for R400 and do a basic sweep from the roof yourself if the flue is straight and accessible. What you can't easily do is inspect the seals, spot warped baffle plates, or identify creosote that has hardened into glaze — which needs mechanical removal. For a once-a-year job, professional is worth it.
Written by
Progress Group
Fireplace, braai and gas specialists since 1990 — showroom in Bellville, installations across Cape Town and the Western Cape.
