Chimney self-check tips for homeowners

Here are some things you can check. (But this doesn't take the place of having the chimney checked by a professional.) 

Chimney tips for homeowners checklist

Condition of exterior chimney

First, take a look at the chimney. Is there anything visibly wrong with it? For masonry chimneys, look for loose or missing bricks, chipped bricks or masonry joints, cracks, holes, a leaning chimney, or anything else that doesn't look right. Use binoculars to check the chimney top. And if the chimney is exposed in the attic, don't forget to check it there, also. 

For metal factory-built chimneys, look for corrosion, loose sections, bending, any movement in windy conditions, and stains. 

Any visible damage to the outside of a chimney is cause to have the chimney checked by a professional. If the outside is damaged, the inside could be in even worse shape. 

Chimney Cap

Is there a cap on the chimney? Water from rain and snow entering chimneys gradually damages the inside of a chimney. Joints between liner tiles gradually dissolve, and corrosive elements in exhaust from furnaces mix with water and slowly weaken the lining. Water pooling at the base damages the chimney structure. Freezing and thawing of water causes expansion damage. A good chimney cap reduces this damage by keeping most of the water out. 

Caps with a screen mesh also keep animals out. Raccoons, squirrels, and birds often nest in chimneys. These animals can bring fleas and ticks into your home, as well as rabies, worms, and other diseases ­ and, of course, animals and their nests can clog the chimney. 

And finally, a cap with a screen mesh helps keep sparks off the roof. So if you don't have one, it is a good investment. Look for a cap that carries a lifetime warranty, and ask your chimney professional for a copy of the warranty card for your files. 

Types of chimney caps: Some masonry chimneys have brick, stone, or concrete caps, raised above the top of the flues on brick or stone legs. Metal caps are also available. Stainless steel and copper caps offer superior durability, and often incorporate a screen mesh to keep animals out and keep sparks off the roof. Most factory-built chimneys incorporate a cap specifically designed to fit that brand of chimney.

Chimney Leaks and Chimney Stains

Next, look for leaks or stains inside the house near the chimney. Peeling wallpaper, stains on the walls, and dampness near the chimney are sure signs of chimney problems. Sometimes these problems are caused by faulty roof flashing around the chimney, but sometimes the source is the inside of the chimney, and this can mean trouble. Missing or damaged flue liners, interior decay, or excessive condensation in the flue could be the culprit. Consult a chimney professional

A note about condensation in flues

Today's gas-fired appliances emit a considerable amount of water vapor. If not vented into a properly-sized flue, condensation in the chimney can become a serious hazard. If you have a gas-fired appliance connected to your chimney it is critical to have the chimney checked periodically by a chimney professional. Don't make the assumption that just because there is no smoke, there is no problem with the chimney. Odorless, colorless carbon monoxide fumes from improperly-vented gas appliances can be fatal.

Base of the Flue

Take a look at the base of the chimney (look in the cellar ­ or for chimneys built up the outside of the house, check the base outside, too). Look for one or more cleanout doors. Take a look inside the door. Using a small mirror and a flashlight, you can look up the flue from the bottom

Some flues have bends in them, so you might not see all the way to the top. But take note of any buildup of soot or debris at the base of the flue, and on the flue walls as far up as you can see. But be aware that even if the base looks pretty clean, the rest of the flue isn't necessarily clean. Most of the action takes place from the appliance up. So the chimney might still need cleaning. 

While you are looking up the flue, try to spot any holes, cracks, or separations. But don't panic if you see something that doesn't look right. It takes a trained eye to determine just what's going on in a chimney flue.

Condition of Appliances

And lastly, you can check the condition of the appliances and connector pipes. Again, this doesn't take the place of a professional check, but it will give you some ideas, and questions to ask. 

Fireplaces

Check the brickwork for wear and breakage. Check the damper. It should open and close easily, without binding on anything. Look up into the smoke chamber, above the damper.

Does the smoke chamber look clean, or sooty? If there is any amount of soot up there, or if you haven't had your chimney cleaned recently, have it checked and cleaned if necessary. 

Wood Stoves

Check the condition of the stovepipe leading to the chimney. If it is rusty, soft, or has holes in it, replace it. Do you see any soot, creosote, or signs of leakage on the outside of the stove or stovepipe anywhere? This could signal an improper installation, and problems with the operation of the stove.

Check both the inside and the outside of the stove for cracks, bulges, warping, rust, or other signs of damage or wear. Most stove doors have a rope-style gasket around the edge for a good seal. Is the gasket in good shape? 

Furnaces

Checking the internal components of a furnace is the job of a furnace technician. But you can check the connector pipe for signs of damage.

Look for rust, soft spots, or leaks. Be careful not to touch any electrical components, or anything attached to the connector pipe. 

If you see anything amiss with the appliances or connector pipes, give your chimney professional a call and find out if immediate attention is warranted. 

Safety Alert

  • Don't check a flue that's currently in use, such as a flue serving a wood stove that is lit or a furnace that is turned on. First, make sure the appliance is off, and remember to wear gloves for protection. Open cleanout doors slowly! There may be a considerable buildup of soot at the base of the flue.
  • Wear protective clothing including eye and ear protection when looking up into chimneys.
  • Pipes might be hot. Be careful! 

 

Here’s a Trick to Check Chimney Flues

Hold a small mirror in the base of the flue, and hold the flashlight so it is pointing at the mirror, from the same angle as your eyes. Then you'll be looking (in the mirror) at the spot that the flashlight is illuminating. You can move the mirror around to see different parts of the flue. It is the same principle as the coal miner's hat with a light on it. The light shines where you are looking. It takes some time getting used to, but it works.

 

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