Fireplaces lull people into a false sense of safety.
They’re quiet. They’re familiar. They look solid. And most of the year, they just sit there doing nothing. Which is exactly why damper problems get missed — sometimes for decades.
Until someone lights a fire.
What the Damper Is Supposed to Do
A fireplace damper has one simple job: open fully when the fireplace is in use and close when it’s not.
Open means smoke and gases go up and out.
Closed means outside air stays outside.
When the damper doesn’t move — or only moves partway — that balance is gone.
The Problem With “It Hasn’t Been Used in Years”
This is where things get risky.
I hear this a lot:
“We never use the fireplace.”
That doesn’t make the damper healthy. It usually makes it worse.
Dampers seize because:
- Rust builds up
- Soot accumulates
- Moisture sits in the flue
- Animals nest above them
- Nobody ever exercises the mechanism
By the time someone does want a fire, the damper hasn’t moved in years.
A Real Inspection Where the Damper Was the Danger
I inspected a home near Lexington, TN where the seller said the fireplace was “decorative only.”
Tried the damper anyway.
It wouldn’t open. At all.
The handle moved, but the plate inside the flue was frozen in place — fully closed. If someone had lit a fire there, smoke and combustion gases would’ve had nowhere to go but into the living space.
That’s not a draft issue. That’s a CO trap.
Why “Partially Open” Isn’t Good Enough
This one surprises people.
A damper that’s cracked open just a bit is still dangerous.
Partial openings can:
- Restrict draft
- Cause smoke rollback
- Allow carbon monoxide to spill into the room
- Overheat the firebox
Fireplaces aren’t forgiving systems. They need a clear path up and out.
The Chimney Doesn’t Fix a Bad Damper
I hear this too:
“But the chimney is tall.”
Doesn’t matter.
A blocked or seized damper cancels out everything above it. The flue can be perfect. The cap can be clear. The liner can be intact.
If the damper doesn’t open, none of that helps.
Why Gas Fireplaces Raise the Stakes
Gas fireplaces make damper issues even more dangerous.
With gas:
- Combustion happens fast
- Exhaust gases build quickly
- CO can accumulate before anyone smells anything
I reviewed an inspection from one of our inspectors in the Little Rock area where a gas log set had been installed without verifying damper operation. The damper was partially closed and rusted in place.
That setup never should’ve been used.
What I Actually Check During an Inspection
I don’t just look at the handle.
I:
- Verify damper movement
- Look for full open and full closed positions
- Check for rust or binding
- Assess accessibility
- Note gas log interactions
- Document limitations if visibility is restricted
If I can’t confirm damper operation, that gets written up clearly.
Why CO Detectors Don’t Make This Safe
CO detectors are a backup — not a permission slip.
By the time a detector goes off:
- The space is already contaminated
- Occupants may be affected
- A dangerous condition already exists
The goal is preventing CO entry, not relying on an alarm after the fact.
What Buyers Should Understand
A seized damper doesn’t mean you can’t have a fireplace.
It means:
- It needs service
- It needs repair or replacement
- It needs verification before use
That’s usually manageable — but only if it’s identified.
The Inspector’s Bottom Line
Fireplaces don’t announce when they’re unsafe.
A damper can be stuck shut, stuck open, or stuck halfway and still look fine from the living room.
That’s why I always check it.
Because a fireplace with a seized damper isn’t cozy — it’s a carbon monoxide problem waiting for the right night.
