Fireplace unused for years: what to check before lighting it

← Back to the blog

We have visited many homes where the fireplace had not been used for 5, 10 or even 15 years. Sometimes the previous owners switched to central heating. Sometimes the family simply stopped using it.

Then someone new arrives, sees the fireplace and wants to light it. We understand. But several things need to be checked first.

Why an unused fireplace is not “safe” simply because it has not been used

It seems logical that if it has not been used, it cannot be dirty. But the reality is different. Time creates problems of its own:

• Bird nests: without a chimney cap, or with a damaged one, birds can access the flue. A nest can completely block the passage of smoke.
• Moisture and condensation: a flue that is not used regularly accumulates moisture, which can damage the inner lining and create porous areas.
• Cracks and deterioration: thermal cycles (cold and heat, year after year) can damage the flue even without combustion. Cracks allow smoke to escape into the structure.
• Dry, hard creosote: if it was last used with damp firewood or incorrectly, hardened creosote may remain, reducing draught and creating a particularly flammable deposit.
• Insects or animals: not just birds. Spiders, wasps and even small rodents may have entered through the flue.

What to check before lighting it

The exterior terminal

Check that the chimney cap is in place and is not bent or blocked. If there is no cap, it is very likely that something is inside the flue.

The flue

Carry out a visual inspection from below with a torch to detect obvious blockages. But a complete inspection requires a professional with the right equipment.

The damper (if present)

Some fireplaces have a lever or damper that closes the flue when it is not in use. Make sure it works and is open before lighting a fire.

Condition of the firebox and lining

Cracks inside the firebox, loose mortar burrs or chipped areas. These are signs that the structure has undergone movement.

The draught test

Before lighting a real fire, you can carry out a simple test: hold a lit match or a burning twist of paper near the fireplace opening. If the smoke rises, the draught is working. If it moves downward or remains in the firebox, there is a problem.

But be careful: this only verifies that the flue is not blocked. It does not check the condition of the flue walls.

What we always recommend

Before using a fireplace that has been inactive for more than 2–3 years, arrange a professional inspection and cleaning. The cost is minimal compared with the risk of a flue fire or carbon monoxide poisoning.