Fireplace Facts

* Earthquakes affect the heaviest parts of the house the most. Masonry fireplaces are very heavy, weighing from 1 to 3 tons on a single-story home.

* Self-contained metal fireplaces, the so-called “zero-clearance” types, are much lighter, weighing from 400 to 625 pounds.

* Most new houses now are being built with zero-clearance fireplaces, which are lightweight and more flexible in a quake than traditional masonry fireplaces.

* Metal chimney flues will sway, without toppling over and are less inclined to pull away from a building. Masonry doesn’t bend, it breaks, whereas metal is more flexible.

* Building a fireplace with a masonry firebox and a metal chimney is possible and combines the best of both worlds--a big firebox and a lightweight chimney. But it is imperative that the metal pipe be approved for high temperatures that can be generated by a masonry firebox.

* Metalbestos is a widely used type of metal chimney flue that is approved to 1700 degrees. It is constructed of stainless steel inside and out, with no asbestos in it and can be used with masonry fireboxes.

* Zero-clearance metal fireplaces use galvanized chimney flues, which must be enclosed, usually framed in wood and insulated. This type of metal flue should not be used on a masonry firebox.

* To install metal fireplaces, contractors must have a C-61 license.

Sources: Seismic Safety/Ed Sylvis Construction; Chuck Nuno, West End Brick ‘N Fire; Building inspectors.