Tips for maintaining a fireplace chimney

A wood burning fireplace is a great addition to your family home, especially in cold weather. Keep yours burning brightly with these suggestions.

Tips for maintaining a fireplace chimney

Chimney maintenance tips

  • The best time to check a chimney is in the spring, right after you've finished using it for the season.
  • From the roof or a ladder, check the top of the chimney first; look for anything that might block it, such as a bird's nest. Then use a powerful flashlight to look down the flue for obstructions. If you find any you can't reach, call a chimney sweep.
  • With the flashlight still shining down the flue, check how much creosote buildup the chimney has. Also check the flue from the fireplace. If the creosote is more than three millimetres (1/8 inch) thick in any part of the flue, have the chimney cleaned.
  • If your flue doesn't have a cap, get one attached. It will keep out foreign objects, small animals and water.
  • If your chimney has two flues — usually one for the fireplace and a smaller one to vent a gas furnace — put a cap on each.
  • Make sure the flashing around the chimney is securely in place and intact. If it's loose or corroded, it won't keep out water, and you'll have plenty of problems. Chimney flashing is complicated to install; have it replaced by pros.
  • The crown is the concrete slab on the top of the chimney that surrounds the flue and acts as a roof to protect the brickwork beneath. If it is seriously cracked, have it replaced by a professional. If it is only slightly cracked, fill the crack with fresh concrete mortar. Also, if the joint between the crown and the flue has deteriorated, re-caulk it.
  • At night with most of the lights in your home turned off, have someone shine a bright work light up the flue from the fireplace while you check all the exposed areas of the chimney throughout the house and attic. If you see any light leaking through, repoint the bricks and have the flue relined by a professional.

Maintaining the outside of your chimney

  • Make sure no trees hang over the top of the chimney. They can be ignited by escaping sparks or create a canopy causing your fireplace to smoke. Trim the trees back so that they're at least three metres (10 feet) from the chimney.
  • A missing or damaged chimney cap can result in moisture inside the chimney. An easy way to check a cap without climbing onto the roof is to place a single sheet of newspaper at the base of the flue the next time it rains. If the paper becomes fairly wet, the cap probably needs repair or replacement.
  • Make sure the flashing around the chimney is securely in place and intact. If it's loose or corroded, it won't keep out water, and you'll have plenty of problems. Chimney flashing is complicated to install; have it replaced by pros.
  • The crown is the concrete slab on the top of the chimney that surrounds the flue and acts as a roof to protect the brickwork beneath. If it is seriously cracked, have it replaced by a professional. If it is only slightly cracked, fill the crack with fresh concrete mortar. Also, if the joint between the crown and the flue has deteriorated, re-caulk it.

A word about wood

  • Only use wood that has been seasoned for at least a year. Because green, unseasoned wood contains up to 50 per cent water, it burns poorly and produces a lot of smoke, which leads to creosote on the chimney's walls.
  • Avoid soft wood, too, which burns fast and gives off more smoke than heat.
  • Keep your firewood dry. When you store it outside, keep it off the ground and uncovered during nice weather; pull a tarp over it when it rains or snows.
  • Never burn painted, stained, or pressure-treated wood in your fireplace. It will release harmful chemicals into the air in your house. You don't want your family to breathe in these chemicals!
The material on this website is provided for entertainment, informational and educational purposes only and should never act as a substitute to the advice of an applicable professional. Use of this website is subject to our terms of use and privacy policy.
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