Archive for May, 2019|Monthly archive page

Common Chimney Problems

In Uncategorized on May 7, 2019 at 9:57 am

Avoiding expensive chimney repairs means you’ll have to annually inspect and maintain your chimney. Don’t get nervous, the inspection is easy; it’s the repairs that could end up expensive.

The majority of the inspection can be done from the ground using binoculars, obviously the repairs cannot. Periodically, a licensed and qualified masonry contractor or chimney sweep will need to get up on the roof and inspect the ‘crown’ or what is also referred to as the “wash”.

The Crown Inspection:

The crown is the concrete cap, which is on top of all the bricks. Its sole purpose is to protect the chimney. Unfortunately, many contractors build it from left over mortar and/or build it too thin. In either case it will crack, break up or fail. When that happens water gets into as well as behind the bricks and the moisture eventually freezes damaging the bricks and with time the entire chimney. Another problem when a ‘wash’ fails is the homeowner often will smell a sooty or sour odor near the fireplace when it rains and even for days after a rain.

The crown should be made from concrete. Either pre-cast and set in place or poured onto the top of the chimney in a form. It should be a minimum of 3-inches thick and the top should be sloped away from the flue liner coming up the middle of the chimney and be caulked with a sticky, viscous concrete caulk between the flue and the wash. Finally, it should overhang the chimney bricks by at least a couple of inches.

The Flue Inspection:

When up on the roof looking down the flue liner, look for loose and broken sections of liner, which would need repairing. Make sure there are no large gaps between sections of liners. Verify it is clean and there are no birds or animals living in the chimney. If you don’t have a metal chimney cap, install one. They keep animals and rain from getting in as well as acting as a spark arrester so your roof doesn’t catch fire. Make sure the flue itself is not cracked or crumbling.

Finally, inspect the flue from the inside of the house by opening the fireplace damper and then look up the flue using a bright flashlight. You’re looking to make sure there are no animals, birds or large amounts of creosote. Creosote, is a by-products of burning soft woods or a lot of wood and it manifests itself to the interior lining of the flue. It looks black and shiny. Some creosote is all right but if it appears to be thicker than the thickness of a nickel, it’s time to call a chimney sweep. If you don’t, you could have a dangerous chimney fire, which could cause the house, attic and roof to catch fire. It could, at the least, seriously damage the chimney.

The Brick Inspection:

Poor workmanship, rain, freeze/thaw cycles along with bad crowns and even antennas can cause the mortar to fail.

Look for loose, crumbling and missing mortar. If you see any, it needs to be repaired or replaced. If you don’t, with time, you’ll have a major rebuilding project on your hands.

If the bricks are not loose and deteriorating, you can probably re-point the bricks yourself for under $50.00 in material. Start by chipping out all loose and damaged mortar using a cold chisel, mason’s hammer and protective eye wear and gloves. Where the mortar is intact and solid, skip over it. Once all loose mortar is gone, clean out all the joints and bricks with a stiff brush. Rinse out all the joints using a wet brush or garden sprayer and water. The rinsing cleans the gaps as well as the entire area so the hot, dry bricks won’t suck the moisture out of the new mortar.

New mortar can be purchased ready-mixed, but you’re better off mixing your own. Use one part Type-N Portland cement, one part hydrated lime to six parts damp, clean sand. Now add the water. If not mixed properly you’ll have the wrong color, it won’t hold, it will deteriorate or it will cause the bricks to spall. Maybe it’s time to call a mason.

If you decide to do it yourself, you will need a large brick trowel along with a small tuck-pointing trowel. Work the mortar into the joints at least one inch deep. Smooth off the excess and when slightly dry use a convex jointer tool to shape the mortar to match the rest of the brickwork. Again, scrape off any excess mortar and clean the bricks. By the way, if you have an old antenna attached to the chimney, remove it. The weight is causing brick and mortar failure.

The Flashing Inspection:

The flashing is the lead, copper, aluminum or galvanized metal where the chimney meets the roof. The flashing can rust or corrode causing it to fail. It can pull loose from the mortar joints or puncture. When it fails you’ll see rotting wood to the sub-structure of the roof in the attic. Eventually you’ll have paint and plaster problems to the ceiling and wall of the room adjoining the chimney.

Never use tar to patch flashing. If the flashing has deteriorated they will need replacing by a roofer. If they are punctured or just pulled loose slightly, they can be reattached and caulked with a quality polyurethane caulk.

Fire Box Inspection:

Look for loose mortar and firebricks. Make sure none of the firebricks are cracked or crumbling. The mortar used in fireboxes is called Refractory Mortar. It is a heat resistant mortar. Tuck-pointing should only be done with refractory mortar.

Inspect the damper. Does it open and close properly? Is the chain or lift arm working easily? If the metal is seriously rusted or warped, it should be repaired or replaced with a chimney top damper. According to Steve Brown of American Fireplace and Barbeque (248-547-6777) they range in price, which depending on size are $200.00 to $400.00 plus $150.00 for installation.

Look above the smoke shelf for fallen debris. If the ash-dump doors are rusted or missing, replace them as well. Look into the ash dump or pit and remove all the old ashes.

If you have a gas fireplace install a ‘C’ clamp on the edge of the damper. The ‘C’ clamp, which is a safety feature, prevents the damper from closing completely. It’s a safety feature. If the gas starts to leak or the pilot goes off, the gas can always goes up the chimney.

Finally, install glass fireplace doors. They save you money on your heating bills, a good quality door cost on average about $300.00.

What to look for when fireplace fails to draw properly:

  • Make sure overhanging trees and branches are cut away from the chimney.
  • Does the chimney meet the 3-inch, 2-inch, 10-inch rule? The chimney should extend at least 3-feet above the roof where it is attached to the roof. It should also be at least 2-feet higher than any portion of the roof within 10-feet of the chimney.
  • If the fireplace back-drafts only when you first light a fire, it’s because of cold downdrafts. You can install a flue top damper to keep the flue warmer, but it’s also a good idea to hold some burning newspaper in the firebox before you light the logs.
  • If your fireplace smokes back into the house on windy days, the chimney may be too short and need to be built up higher.
  • If the fireplace constantly back drafts, have the flue cleaned. If that doesn’t work, you may have a problem with the damper. The flue may also be too small for the firebox. Sometimes raising the metal grate up onto bricks solves the problem. If it doesn’t, check with a certified chimney sweep.
  • Another cause may be that the house is too tight. Slightly open a window on the first floor. If it corrects the problem, install outside air to the firebox or a product called Equliz-Air (734-462-1033) to your HVAC system.
  • If the fireplace, only back-drafts as the fire is embering down, the flue may be too large. Install glass fireplace doors.

Hiring a Chimney Sweep:

Anyone you hire to clean or repair your chimney should be qualified. You should also make sure they have insurance and see a copy of the policy. The insurance (which is called Errors and Omissions) should cover any damage they do, It should also provide coverage of the person doing the work if they should fall off the roof and is injured or killed. You should check out anyone you plan on hiring with the Better Business Bureau.

Chimney professionals are certified or credentialed by the National Chimney Sweep Guild and/or the Chimney Safety Institute of America (CSIA). They are non-profit professional organizations that promote safety and education to their members. They can be contacted by going to www.NCSG.org or www.csia.org.

There is no licensing for chimney sweeps but to do the repairs they must be licensed by the State of Michigan as a contractor. Expect to pay at least $100 to $150.00 to have your chimney cleaned. This is a business that is ripe for scam artists. Anyone offering less expensive (such as $49.95) chimney cleaning services probably will not be doing a thorough job.


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