G. CONSTRUCTING A CHASE
A chase is a vertical boxlike enclosure built around the chimney and fireplace. A chase may be constructed for the fireplace and chimney or for the chimney only. It is most commonly constructed on an outside wall.
In cold climates, it is recommended that the chase floor be insulated using batt type insulation between the floor joists.
Three examples of chase applications are shown in Figure 20.
1.Fireplace and chimney enclosed in an exterior chase.
2.Chimney offset through exterior wall and enclosed in chase.
3.Chase constructed on roof.
1.Materials
a.The chase is constructed using framing materials much the same as the walls in your home. A variety of materials may be used including brick, stone, veneer brick, or standard siding materials.
b.In constructing the chase, several factors must be considered:
1)Maintain a 2 in. air space around the chimney.
2)The chase top must be constructed of noncombustible material.
3)In cold climates, a firestop spacer should be installed in an insulated false ceiling at the 8’ level above the fireplace assembly. This reduces heat loss through the chase.
4)In cold climates, the walls of the chase should be insulated to the level of the false ceiling as shown in Figure 21. This will help reduce heat loss from the home around the fireplace.
Figure 20 - Chase Constructions
Figure 21 - Chase Assembly
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