Factory built fireplaces are installed in most new home construction because of the more affordable cost. They are designed to be installed inside of a wooden chase and have two main assemblies.
Firebox Assembly: This is where you actually build your fire. It is made of metal that is covered with refractory panels. These panels resemble brick but are actually in in four pieces: floor panel, two side panels, and a back panel). Over time these panels can crack and need replacement. There is a Damper built into the firebox assembly that you manually close when not in use to keep out cold air.
Flue Assembly: The two most common flue assembly’s on a Pre-fab fireplace snap-lock into the top of the damper on the firebox assembly. The older factory built fireplaces have triple wall pipe but all the newer fireplaces are double wall pipe. The inner pipe connects direct to the damper and runs to extend out the top of the chimney. The outer wall pipe snaps to an adapter around the damper and runs the same length as the inner pipe, extending out of the chimney chase. The function of the inner pipe is to exhaust all the heat and by-products of combustion to the outside of the home. The outer pipe allows air flow between the two pipes and acts as an insulator to keep combustible material in the chase from igniting.
Cap: We install chimney caps that connect to the inner and outer pipe to keep out rain and animals. This cap must be listed for use with your particular factory built fireplace.
Chase: The chase is the wooden structure that surrounds your factory built fireplace firebox and flue pipe. It is typically built with 2×4 and plywood construction. There should be fire-stops installed inside the chase every 8 feet. It is typically covered on the outside with the same siding material as on the house itself.
Chase Top: A properly made chase top is very important to keep the life of your chimney chase! Being that the firebox and flue pipe are inside a wooden chase, the top of the wooden chase needs to be covered with a chase top to prevent water from entering the chase and your home. During construction we have found that chase tops are usually installed with the cheapest of materials, therefore rusting and needing replacing when the home is only about 10-15 years old (if not sooner). We replace rusted chase tops with individually made stainless steel chase tops. Our chase tops have bends from the center to each corner and a drip edge around the sides. Our stainless steel chase tops come with a lifetime warranty to never rust. Neglecting to address these corroding chase tops can lead to having to rebuild the entire wooden chase. It is very important to ensure your chase top is in good working order.