How to Tell if a Chimney Needs Cleaning?

Understanding Chimney Buildup

To know if your chimney needs cleaning, you first have to understand what a chimney sweep actually removes. A chimney isn’t just filled with simple dirt. It’s filled with a mix of soot, creosote, and sometimes, physical blockages.

What is creosote and how it forms: Creosote is a highly flammable residue that is left behind by burning wood. It is a byproduct of smoke and gases, which, as they travel up the chimney, condense and stick to the inner walls. It can be a powdery substance, a sticky tar, or a hardened, shiny glaze. This glazed creosote is the most dangerous kind and is a major fire hazard.

Difference between soot, creosote, and blockages: Soot is the harmless black powder that is easy to brush away. Creosote, on the other hand, is sticky and dangerous. A blockage is a physical object that is stuck in the chimney, like a bird's nest or a broken piece of brick.

How often chimneys typically need cleaning (general guideline: once a year): For most homeowners, a chimney should be inspected and cleaned at least once a year. This is a general rule that works for most people, but some wonder if this applies to newer systems. Our guide on do modern chimneys need cleaning answers that question.

Signs Your Chimney Needs Cleaning

Your chimney will often give you clues when it's in need of attention.Here are some clear signs that will help you understand How to Tell if a Chimney Needs Cleaning? by listening to what your fireplace is telling you.

• The Room Fills With Smoke: The entire purpose of a chimney is to pull smoke out of your home. If you light a fire and the room fills with smoke, it is a clear sign that the chimney is not working properly. This is usually due to a blockage or a lot of creosote buildup that is restricting the airflow.
• Increased Soot and Creosote: If you notice that you have a lot of black, flaky material collecting around the fireplace opening, it is a sign that your chimney is very dirty. The same goes for any oily, black substance that you see on the brickwork or stonework.
• Animals Get Trapped: Have you ever heard strange noises coming from your chimney? It could be a bird or a squirrel that has fallen in and can’t get out. In a place like Cambridge, Massachusetts, it’s not uncommon for squirrels to try and nest in a chimney. Animals and their nests are a major fire hazard and a clear sign that your chimney needs to be cleaned and checked for a cap.
• Struggle to Keep the Fire Going: A fireplace needs oxygen to burn properly. If your chimney is clogged, it can’t pull in the oxygen it needs to keep the fire going. If you are having a hard time getting a fire started or keeping it burning, it’s a sign that you have a problem.
• The Damper Is Black: The damper is the small metal door that you can open and close to let smoke out of the fireplace. When it is clean, it is a shiny black. If you open it and see a lot of soot or creosote on it, it is a clear sign that your chimney is dirty.
• Visible Oily Marks on Your Fireplace Walls: If you can see an oily, dark stain on the walls of your fireplace or on the outside of your chimney, it’s a sign that creosote is backing up and leaking through the masonry. This is a very serious problem that can cause a lot of damage to your home and is a major fire risk.