How To Repair A Fireplace Damper

Time: 1 ½ hours

That snap, crackle, pop in your fireplace makes for super-cozy evenings at home, but where there is fire, there is smoke. Clean or replace your fireplace damper to keep the smoke outside and the warmth inside. (Psst...the damper is the heavy metal door between the chimney and the firebox.) Don't worry — they'll still be plenty of time left to curl up in front of the fireplace.

What's in it for you?

Save energy
Keep smoke out of your home
Maintain your fireplace

(Show me how)

Fix Your Fireplace Damper to Keep the Smoke Out

Trash the ashes. PSA: Stay safe and make sure everything's cooled down. Grab a broom and dustpan and sweep the ashes into a metal pail or dustpan.
Find your damper. Protect yourself from soot and other chemicals with a pair of goggles and a dust mask. Shine a light inside your fireplace and find the damper (a heavy metal door between the chimney and firebox). It'll probably need a good brushing to get rid of all the soot so grab a wire brush and get to work. Note: If you see a chain hanging in the upper corner of your fireplace instead of a door, you have a chimney-top damper. You'll need to get up on the roof to fix that one.
Test your damper. Open and close the damper a few times to make sure it's in good working order. Did you do this with a knob just outside the fireplace? If so, you should also look just beneath the damper for a spiraled metal cylinder. Give this "worm gear opener" a spray of lubricant to keep it turning smoothly.
Adjust the alignment of the damper plate. Years of heat exposure may have caused irreparable damage, but sometimes a simple realignment can fix the issue. The plate on the bottom of the damper normally pivots in a notch along the back of the damper's opening. If it's not doing that, shift the damper plate until it does.

(Show me how)

Broken Damper Plate? Replace It.

Remove the damper plate. Cracks, warps, and missing pieces mean you'll need to replace the damper plate. Pull out the cotter pin — a bent wire fastening the damper plate to an opener (more on that in step 7) — and slide the plate out of the damper opening. (You might need to unbolt a rod or remove some hinge pins from the sides of your fireplace first.)
Get a new plate and install it. Head over to your local hardware store with your old damper plate and get a new one that matches. It'll install more or less like the one it's replacing — slide it in, replace the bolts or hinge pins, and reinsert the cotter pin.
Replace the damper plate opener. Most fireplace dampers come standard with a lever opener, meaning you push a lever inside the fireplace with a fire iron to open the damper. If you've tried cleaning and adjusting the plate but the damper still won't open, head over to your local hardware store with your old opener and get a new one. Install a lever opener by sliding the lever through the bracket inside the damper and reattaching the cotter pin.
Replace the entire opener mechanism if you have a worm gear opener. Some fireplaces have worm gear openers, which you activate by turning a knob outside the fireplace. You can try tightening the screw on the opener but if that doesn't work you'll need to replace the entire mechanism. Remove the plate that's behind the knob outside your fireplace. Thread a steel rod through the tube, the worm gear and the front and back holes in the damper. Replace the cotter pin, tighten the screws and test the knob to see if the damper opens. Put the grate back, and tada — your fireplace is ready for action.

Pro Tip: Instead of trashing ashes, add them to your soil. Wood ashes add nutrients to your garden and reduce the amount you're contributing to landfills. Win-win!