There is no completely effective way of preventing earthquake damage to an unreinforced masonry chimney. The best solution is chimney rebuilding which is the removal of the chimney down to the top of the firebox and installation of a factory-built, metal flue enclosed in conventional 2×4 steel-stud framing.
1. The damaged brick chimney is first removed down to the firebox throat.
2. A factory manufactured transition box is installed from the firebox to the new flue.
3. Steel reinforcements (rebars) are doweled into the bricks with high strength epoxy. Additional rebar is placed in the form. Concrete is then placed into the form to create a transition bond beam. This concrete bond beam may have to be secured to the house depending on its location.
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4. A code approved, factory-manufactured, HT-rated chimney flue for wood-burning fireplace is then installed.
5. A steel stud chimney is constructed to enclose the new flue. The steel stud framing is bolted to the concrete bond beam below and extends above the roof line a certain distance as required by code.
6. The new chimney chase may need to be braced to the roof structure or ceiling joists depending on its height above the roof line.
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7. A factory manufactured spark arrestor is installed.
8. Lath and stucco are applied to the exterior of the chimney chase to match the exterior of the house. The new stucco may have to be painted to blend into the surroundings.
9. Finally, a shop-fabricated sheet metal chimney chase cap is installed to keep out the elements.