Heatilator • LM42 • Installers Manual • 4087-901 • Rev A • 04/14/16
15
C. Construct the Chase
A chase is a vertical boxlike structure built to enclose the
fireplace and/or its vent system. Vertical chimneys that
run on the outside of a building must be installed inside a
chase. See Figure 3.4.
Construction of the chase may vary with the type of build
-
ing. Local building codes MUST be followed.
Hearth & Home Technologies recommends:
-
The inside surfaces be drywalled and taped (or
the use of an equivalent method) for maximum air
tightness to the false ceiling.
- In cold climates, the walls of the chase should be
insulated to the level of the false ceiling as shown in
Figure 3.4. This will help reduce heat loss from the
home around the fireplace.
-
Holes and other openings should be caulked with
high temperature 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 3.4 Chase Assembly
1
2
3
All outside walls should be insulated.
Figure 3.5 Chase Applications
1. Fireplace and chimney enclosed in an exterior chase.
2. Chimney offset through exterior wall and enclosed in chase.
3. Chase constructed on roof.
• Requirements for constructing the chase:
- A firestop spacer and attic insulation shield should
be installed at the false ceiling. See Figure 3.4.
- The chase must be properly blocked to prevent blown
insulation or other combustibles from entering and
making contact with fireplace or chimney.
- The chase top must be constructed of non-
combustible material.
Three examples of chase applications are shown in Fig-
ure 3.5.
WARNING! Risk of Fire! DO NOT seal area between fire
stop opening and chimney pipe except where they enter
the attic or leave the warm air envelope of the home (use
600° F sealant).
WARNING! Risk of Fire! You must maintain a minimum 2
in. (51 mm) air space clearance to insulation and framing
surrounding the chimney system.