Possible ways to fix a faulty chimney

When a fireplace is not ventilating properly and the smoke is pushed into a room, this is hazardous to your health. Considering the great enjoyment (not to mention the resale value) of the fireplace in your home, it’s good to know you can choose effective solutions; the cost can range from $0 to about $3,000, depending on what the issue is.


  1. If the chimney smoke sneaks into the house only on windy days, the problem is resulting from too short of a chimney or because of environmental situations beyond your control. Consider extending the chimney or install a wind deflector or a fan.
  2. The backflow usually occurs when the operation of the escape fans, including clothes dryers, exert negative pressure in a sealed house. Open a window or install an air intake kit for supplying necessary combustion air. A leaky attic in a multi-story home can create a chimney effect and cause chronic depressurization. The solution is to seal all openings between the living space and the attic.
  3. The inadequate flow can occur when the size of the fireplace opening is too large for the size or length of the home. Compare the size of the home with the standards published in architectural manuals, available in the reference section of most public libraries. Solutions range from reducing the size of the opening with a protective metal fume for large projects such as the installation of a fireplace insert, the reconstruction of the firebox, adding height to the chimney, and the installation of a fan.
  4. Install a windbreaker. Consult with a professional who can install a wind diverter cap for fireplaces. While the skill itself is relatively simple, working safely with a chimney cap is not, and some providers will sell products only to professionals.
  5. Install a chimney fan. These specialized fans allow for specific conditions, as extreme heat and corrosive gases will pass through them.
  6. Increase the height of the chimney. A chimney must be 2 feet (60 cm) above the ceiling or any 10 feet away from other structures. If it is not high enough, ask a bricklayer to extend a masonry chimney, or a suitable professional to extend a metal.
  7. Replace lining to extend the homers, if the old chimney flue is too small, there may be enough space between the chimney and brick to open the existing conduit and install a new one. A metal coating to a chimney flue costs around $2,000, and a solid flue, which is poured around a recess inside the chimney way, costs $500 to US $ 1,000. Both must be installed by professionals.
  8. Install an air intake duct in the firebox. Remove the outer refractory and brick or stone cladding, and then drill a hole for a stainless steel vent that will extend from the outside directly to the fireplace. Alternatively you can install some models in the ashtray below the firebox to let in air through a vent special floor.
  9. An easier alternative is to install a DIY air intake vent through the wall of the room. Although the vent itself is only available in stores chimneys, installation is identical to a dryer, a common DIY project.
  10. Lower the threshold with a metal shield, such as Smoke Guard. This shield, available in different widths, heights and finishes in stores that specialize in fireplaces, falls into place. Some glass doors for fireplaces can also effectively reduce the threshold.
  11. If comfort, energy efficiency and appearance of your fireplace is what you like most, installing a sealed gas combustion can resolve any problem.

Tips & Warnings

  • To do a depressurization test open a window in the fireplace room, wait an hour and light the fire. If the smoke still enters the room, depressurization is not the problem.
  • Deal only with licensed and experienced professionals, and get references.
  • Be sure to obtain necessary permits and inspections.
  • The depressurization can increase the infiltration of radon and cause carbon monoxide poisoning from combustion appliances such as water heaters, furnaces and boilers.
  • Because of the high costs and considerable risks involved in changing a fireplace, never act without consulting a professional and local building department.