By James Rodriguez, Central Chimney Service.
You cannot inspect your own chimney properly, and nobody should pretend otherwise. What you can do is a twenty-minute walkthrough that tells you how urgently to book someone, which is genuinely useful information to have in August rather than in November.
Before you start
Stay off the roof. Everything below is done from inside the house or from the ground, and the roof portion is exactly the part that needs someone with a harness and a reason to be up there.
You will want a bright flashlight, a small mirror if you have one, an old towel, and gloves. Open a window in the room first — you are about to disturb settled soot, and the room will be easier to keep clean with a bit of airflow.
Inside the firebox: eight minutes
Open the damper fully and confirm it swings freely and then seals when closed. A damper that grinds, sticks halfway, or will not seat is your first finding.
Shine the light up. You are looking for four things: daylight at the top, which is normal on an open flue; a heavy black glassy coating, which is glazed creosote and needs professional removal; nesting material or debris on the smoke shelf; and any loose or fallen fragments of tile or mortar in the firebox. Then look at the firebox itself for cracked or missing refractory panels, gaps in the mortar joints between firebricks, and rust streaking down the back wall. Finally, hold a hand near the open damper — on a cool morning you should feel some air movement. None at all suggests a blockage.
From the ground outside: seven minutes
Binoculars help here. Look at the top of the stack: is there a cap, and is it intact and level, or is it missing, rusted, or askew? Look at the crown for visible cracks or missing corners.
Work down the brick faces looking for pale patches where the face has flaked off, joints that have eroded, and biological growth on the shaded side. Where the chimney meets the roof, look for lifted or rusted flashing, or a smear of roofing tar where flashing should be. Then check the ground and gutters for brick or mortar fragments. Around Minooka and the surrounding area, wind-driven rain from the open west and south is what drives most of the water damage we see, so pay particular attention to those faces [Observed].
The rooms next door: five minutes
This is the step people skip and it catches the most expensive problems. Walk the room on the other side of the chimney wall, the room above it, and the attic if you have access.
Look for staining or bubbling paint on the wall or ceiling adjacent to the chimney, a musty smell near it, daylight visible around the chase in the attic, and any damp or discolored framing where the chimney passes through. Water travelling down a chase shows up in these places long before anyone notices anything at the fireplace itself. Our DIY chimney care guide goes through each of these checks in more depth.
Write down what you find, with the date and a photo where you can get one. A single walkthrough tells you the current state. Two walkthroughs six months apart tell you whether something is moving, which is far more useful. A hairline crack that looks identical in March and in August is a different situation from one that has visibly opened over a winter, and that distinction is what should drive how urgently you act. It is also the information that makes a conversation with a sweep productive instead of speculative.
What to do with what you found
Anything on this list means book an inspection; none of it means the situation is hopeless. Glazed creosote, a stuck damper, debris on the shelf, or fresh masonry fragments move it up the queue. Book a chimney inspection and mention specifically what you saw, so the visit starts from your findings.
Central Chimney Service is insured and bonded, covers Minooka seven days a week from 7 AM to 7 PM, gives the price up front, and brings 29 years of doing this locally. Call (815) 305-5510.
Frequently asked questions about checking your own fireplace
Is it safe to open the damper and look up the flue?
Yes, with a window open and reasonable care. Wear gloves, keep your face out of the opening while you first crack the damper, and expect some loose soot to fall. What you should not do is climb into the firebox or reach up past the damper blindly.
What does glazed creosote look like?
A hard, shiny black or dark brown coating that looks almost like tar or enamel on the flue walls, rather than the dull, flaky soot most people expect. It is the most dangerous stage because it is highly combustible and cannot be brushed off.
Should I see daylight when I look up the chimney?
On a straightforward open flue with a cap, you will typically see a dim light or the pattern of the cap screen. Complete darkness on a flue that should be open suggests a blockage. Chimneys with offsets legitimately show no daylight, so this is a soft signal rather than proof.
How do I test the damper properly?
Open it fully, close it fully, and repeat a couple of times. It should move without grinding, hold in the open position without being propped, and seat firmly when closed. Resistance and squealing usually mean corrosion, which means water.
Is a small crack in the firebox brick a problem?
Hairline cracks in refractory mortar joints are common and often monitored. Cracks wide enough to fit a coin, missing chunks of refractory panel, or gaps that expose the material behind the firebox are a different matter and should be looked at before you burn.
Can I do this check on a gas fireplace?
Parts of it. The exterior masonry check, the venting terminal, and the neighboring-room water check all apply. Do not disturb the logs or the burner assembly, since log position is engineered and moving them causes sooting.
What if I find a bird nest?
Do not light a fire and do not poke at it. If birds are actively nesting they may be federally protected and the nest has to stay until they leave. Have someone identify what is there from above before anything is removed.
How often should I do this walkthrough?
Twice a year is plenty: late summer before the heating season, and again in spring after the winter has done its worst. It supplements an annual professional inspection rather than replacing it.
Published August 19, 2026 · Last updated August 9, 2026