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Flue Replacement
 
 
Over 100,000+ patent flues* serve typical San Francisco houses, duplexes, and apartment buildings. Built of a ceramic flue with a sheet metal enclosure inside of a chase structure, patent flues are vulnerable to earthquake damage and the elements. If used while damaged, they can pose serious fire and health hazards.

Okell’s Fireplace uses an anchor plate repair to replace all of the patent ceramic flue with new Class A (triple wall) metal flue maintaining the proper flue size.

The following list (also illustrated below) is the typical process of replacing your damaged patent flue system with new Class A flue. Once complete, you and your family will be able to safely enjoy the warmth and ambience provided by your fireplace.

1. Our installation crew use site protection to protect your home

2. The wall above the fireplace is opened to expose the damaged flue

3. The damaged flue is exposed

4. We carefully remove the damaged flue

5. We install an “anchor plate” to the top of your fireplace box so we can then attach     your new Class A flue

6. A new Class A flue pipe is run up through the existing chase

7. The new flue pipe is attached to the anchor plate

8. Finishing touches are applied at the top of the new Class A flue

Many of our competitors use a single wall flexible liner with insulation in the throat area that reduces and limits the flue size. We strongly do not recommend this option. A permit cannot be given for this type of work because it does not meet the manufacturer’s requirements for the use of the product. This method also limits the flue volume and typically makes the fireplace smoke. We have found no evidence that this method is standard for the industry or can be certified in any way.

Please note that replacement of this type of flue system is the only approved way to repair your fireplace properly. Metal flexible liners installed inside this style flue system is NOT a proper repair and a permit and inspection by the city cannot be obtained.



Flue Relining
This is an example of a cross section of an old patent flue. It consists of a ceramic liner and one light metal casings separated by an air gap.
 
* In San Francisco, a patent flue is commonly used either instead of a lined chimney, as a vertical extension of a masonry chimney, or as a flue within a decorative chimney. The patent flue, so called because its design was covered by a registered U.S. patent, was mentioned in the 1906 San Francisco Building Law as an acceptable alternative to the traditional brick flue and was used during the rebuilding that followed the 1906 earthquake. It is formed from a stack of mortared ceramic tube sections about one inch thick, surrounded by an air gap of approximately one inch, and an outer sheet metal jacket.
 
 Site Protection
Opening wall to expose the damaged flue
Damaged flue is exposed
1. Site Protection
2. Opening wall to expose the damaged flue
3. Damaged flue is exposed
Removing the damaged flue
 Installing an anchor plate
 Running a new Class A flue through the chase
4. Removing the damaged flue
5. Installing an anchor plate
6. Running a new Class A flue through the chase
New Class A flue is attached to the anchor plate
Finishing details are taken care of on the roof
7. New Class A flue is attached to the anchor plate
8. Finishing details are taken care of on the roof
Okell's Fireplace, Fireplaces, San Francisco, CA
Remodeling and Home Design
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