Chimney Re-Lining | The Chimney Swift Ltd

By: The Chimney Swift  09-12-2011
Keywords: Oil, Stainless Steel, chimney

re-lining chimney with wood stove

The Ontario Building Code states in section that " Every masonry or concrete chimney shall have a lining of clay, concrete, firebrick, or metal."

A proper liner for each flue in a chimney is important.

  • in order to provide a gas and water-tight conduit
  • to completely contain the by-products of combustion
  • to safely exhaust those by-products from your home.

We specialize in re-lining chimneys which service appliances that use gas,oil and wood.

We also specialize in difficult installations, such as really tall chimneys (see photo's above).

Gas and oil-fired appliances, especially newer ones, are extremely efficient. This means more heat for you in your home, but much less heat going up the chimney. Less heat in the flue means a substantial amount of condensation buildup, especially in the portion of the chimney which extends above the roof. This part of the chimney is not sheltered by the house and is therefore much colder. There is now water running down the inside of your flue.

If the flue is unlined, or has a (non watertight) clay tile liner, this water will now get into the brickwork itself. Freeze / thaw cycles throughout the winter will now cause the chimney to rapidly deteriorate.

Any appliance, whether gas, oil or wood, will perform best with the proper size flue.

re-lining chimney with oil appliance

An undersized flue will have severe flow restriction and will spill flue gases and smoke into the home.

An oversized flue will be very cold, have poor draft and this will lead to excessive condensation being present in the flue. Stainless steel is an excellent material to use to re-line a flue to the proper size for the appliance.

Stainless steel is also an excellent material for the lining or re-lining of flues servicing wood-burning appliances.

Stainless steel is much better able to withstand the stress of thermal cycling and thermal shock which occurs frequently when burning wood. Going from a cold system to a really hot fire rapidly, such as when burning a lot of paper, puts a lot of stress on the flue lining material. Clay flue tile cracks quite easily - examples of which are shown below. For most applications we use the type 316TI stainless steel liner manufactured by Chim-flex.

Go to our photo gallery of chimney problems to see more examples of what can happen without a proper flue lining.


Do you heat with oil? If so, you may have already or will soon be dealing with the requirements of newer oil-fired appliances.
  • New oil furnaces are as efficient as gas furnaces.
  • Higher efficiency means more heat in your home and less heat going up the chimney.
  • This can lead to excessive condensation (moisture) in the chimney.
  • A stainless steel liner is a must to ensure that the flue is the correct size to properly vent the furnace.
  • A tee is now required at the base of all stainless steel liner installations. Since the requirement to have a tee was only mandated with the 2000 version of B-139 (the Oil Installation Code), some older liner installations may not have the tee.

There are reasons why a tee might not have been installed:

  • not physically possible due to space availability.
    (Manufacturers have tried to address this issue by re-designing their tees to allow for easier installation.)
  • installer not aware of necessity.

Typically, homeowners are being given 90 days to comply before oil delivery is halted.

Direct-vent oil appliances

The photo above shows the outside termination of a direct-vented oil furnace. It is a good example of the type of problems associated with this type of venting:

The termination is right under a window. Under certain wind conditions, toxic fumes can be drawn back into the house (probably the most common complaint with this type of vent).

The unsightly black circle in the snow is oil soot. It is not uncommon for this type of oil vent to perform poorly, leading to excessive soot buildup. It will certainly kill any plant material in this area.

Oil soot is very corrosive. It does not show up well in this photo, but the brick immediately above the vent is deteriorating. The vent termination is also corroding.

The following photos show what can happen when aluminum is used to re-line a flue for an oil-burning appliance. (Stainless steel is required by code).
While the photo on the left is not very clear, you can see the top of what is left of the aluminum liner. It is down about two feet from the top. The white on the sides is frost.
The photo on the right show severe corrosion of the aluminum top plate, which is supposed to seal the top of the chimney and is part of the support for the flue liner.

Call today for more information or a quote!

Keywords: Building Code, chimney, Oil, Stainless Steel, Steel Liner

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