FAQExistChim

Can I use my existing chimney for my new wood stove?

I already have a chimney. It was used by a woodstove several years ago but has not been used for a while. I would now like to use it for a new wood stove. I can do this, right?

I have a wood stove and chimney and want to upgrade the stove. I can still use my existing chimney, right?

The answer to this question, in most cases, is "maybe". Without a careful inspection of the existing chimney system we cannot say for sure if we will be able to hookup your new stove to your existing chimney. Here's a list of some of the things we look for when we inspect your chimney:

Is the chimney the right type for a wood stove?

"Didn't I just tell you that the chimney was being used for a wood stove?" Yes, we heard you. But we still need to double-check that the existing chimney meets all the qualifications for use with a wood stove. We have seen many wood stoves hooked up to chimneys that were never intended to be used for wood stoves.

If the chimney is a metal "Class A" type chimney has it been tested to the UL103HT standard?

Many Class A metal chimneys in use by wood stoves were not tested to the current safety codes now in place for wood stoves. Class A chimneys that were tested to the UL103 standard should not be used for wood stoves. These chimneys should be replaced and upgraded to the new "Type HT" UL103HT standard. All new wood stoves specifically state in thier instruction manual that the chimney used must meet current safety codes. For Class A metal chimneys this means being tested and listed to the UL103HT standard.

Does the interior liner show signs of fatigue from a past chimney fire? Does the exterior casing show signs of wear such as pitting or rust?

If the metal surfaces of the chimney show signs of wear due to the age of the system it should not be used for a new wood stove installation. Chimneys that have been damaged should be replaced with a new chimney system that can be verified to meet all the rules of safety.

Is there sufficient air clearance between the chimney and any combustibles? Is the chimney properly supported and protected?

If the existing metal chimney was not installed with the correct clearances to combustibles then the chimney should either be re-installed or replaced. If the chimney pipe is of the proper type and condition it may be possible to re-install the same chimney with the correct clearances. If not, the entire chimney must be replaced. The same applies to proper support and protection. If the chimney pipe itself passes inspection, the supports or flashings may be added to the existing chimney without the need for complete replacement.

If the chimney is a masonry chimney system, is it structurally sound? Are there any cracks or loose stone or bricks? Is there proper clearance to combustibles? Is there a proper liner in place?

Unlike pre-fabricated metal chimney systems (Class A) most masonry chimney systems are not tested and listed to a specific safety code. However, all masonry chimneys that will be used by a wood stove must meet minimum codes for safety established by NFPA211 - a document accepted by most building codes for the proper construction and use of chimneys for soild fuel appliances. If your masonry chimney does not meet the requirments of NFPA211 it will need to be upgraded before we can hook up your new wood stove. This may require some simple repairs or it may mean abandoning the existing structure and the installation of a new chimney. In any case we cannot hookup to a masonry chimney that is not code compliant.

Conclusion

If your existing chimney passes our inspection and is approved for use with your new wood stove we will hookup your new wood stove to your existing chimney. However, if your existing chimney does not pass our inspection we may need to either replace it or upgrade the system so that it meets current safety codes. (Note that your hearth must also pass inspection).

For a wood stove installation to be considered safe the entire system must meet the rules of safety. This means the chimney, the stove, and the hearth must all meet current safety codes. The Cracker Mill will not hook up to an existing chimney (or hearth) unless it meets the current safety code for wood stoves as established by the state building codes in effect at the time of installation.

Sincerely,

The Staff at the Cracker Mill Hearth and Emporium