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Page 14
433-1390G
September 1, 2008
R
7100FP EPA Woodburning Fireplace
E. Construct the Chase
A chase is a vertical boxlike structure built to enclose the fire-
place and/or its vent system. Vertical chimneys that run on
the outside of a building must be installed inside a chase.
In cold climates, it is recommended that the chase be well
insulated using batt type insulation between the joists.
Construction of the chase may vary with the type of build-
ing. These instructions are not substitutes for the require-
ments of local building codes. Local building codes MUST
be checked.
Chases should be constructed in the manner of all outside
walls of the home to prevent cold air drafting problems. The
chase should not break the outside building envelope in any
manner. All outer walls need to be insulated.
Building codes require false ceiling and ceiling firestops at
each floor of the chase or every 10 ft (3048 mm) of clear
space to control spread of fire.
Walls, ceiling, base plate and cantilever floor at the first level
of the chase should be insulated. See Figure 14.1. Vapor
and air infiltration barriers should be installed in the chase
as per regional codes for the rest of the home. Additionally,
Hearth & Home Technologies recommends that the inside
surfaces be sheet rocked and taped (or the use of an equiv-
alent method) for maximum air tightness.
Holes and other openings should be caulked with high tem-
perature caulk or stuffed with unfaced fiber glass insulation.
Ceiling
Firestop
Metal Chase Top
Round Termination Cap
False Ceiling
Insulation in the
outside walls
of the chase
Attic
Insulation
Shield
Chimney
Ceiling
Firestop
Tabs
False Ceiling
False Ceiling
Insulation
Insulation
Storm Collar
Figure 14.1 Chase Assembly
1 2 3
All outside walls should be insulated.
Figure 14.2 Chase Constructions
1. Fireplace and chimney enclosed in an exterior chase.
2. Chimney offset through exterior wall and enclosed in
chase.
3. Chase constructed on roof.
Materials
Three examples of chase applications are shown in Fig-
ure 14.2.
a. The chase is constructed using framing materials much
the same as the walls in your home. A variety of siding
materials may be used including brick, stone, veneer
brick, or standard siding materials.
b. In constructing the chase, several factors must be con-
sidered:
1) Maintain a 2 in. (51 mm) air space around the chim-
ney.
2) The chase top must be constructed of non-combus-
tible material.
3) In cold climates, a firestop spacer should be installed
in an insulated false ceiling at the 8 ft. (2438 mm)
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 14.1. This will help reduce heat loss from the
home around the fireplace.