10
Figure 11
REDUCED CLEARANCE SUPPORT (RCS)
FRAMED OPENING REQUIREMENT
(Cathedral support (CS24) dimensions are the same for all
diameters. Use 8’’ size reference for the frame opening)
Chimney
Size
6”
7”
8”
Roof
Slope
A
B
A
B
A
B
x/12
0
12-1/8 12-1/8 13-1/8
13-1/8
14-1/8
14-1/8
2/12
12-1/8 12-1/4 13-1/8
13-1/4
14-1/8
14-3/8
4/12
12-1/8 12-3/4 13-1/8
13-7/8
14-1/8
14-7/8
6/12
12-1/8 13-1/2 13-1/8
14-5/8
14-1/8
15-7/8
8/12
12-1/8 14-1/2 13-1/8
15-3/4
14-1/8
16-7/8
10/12
12-1/8 15-7/8 13-1/8
17-1/8
14-1/8
18-1/2
12/12
12-1/8 17-1/8 13-1/8
18-1/2
14-1/8
20
HOLE SIZE
DOWN
B
ROOF SLOPE
INCHES
SIDES OF HOLE MUST
BE VERTICAL
12 IN
ACROSS
SLOPE
A
X
NOTE:
The Reduced Clearance Sup-
port comes with a collar. It can be
discarded for this application.
Step 1: Locate the chimney in a
convenient location as near
as possible to the appliance
outlet. Cut and frame an
opening in the roof for the support. The sides
of this frame must be vertical.
See Figure 11
Step 2: From below, push the Support into the
framed opening in the ceiling.
NOTE:
The bottom portion of the support must
project below the ceiling to ensure appropriate
clearances to stovepipe. See Table 6.
Step 3: Using a level, make sure the support is ver-
tical. If the support extends above the roof,
cut it flush with the top of the roof. Nail the
support to the framed opening using (12)-3”
spiral nails or #8 x 1 1/2” wood screws.
See Figure 10
Step 4: Place first chimney length into the support.
Twist to lock into place. Wrap the insulation
pad (RCS) around the chimney, then slide it
down within the support box. Make sure the
insulation makes contact with the bottom of
the support. Additional pieces of insulation
can be loosely tucked down within corners.
Do not compress insulation, this reduces
effectiveness.
With a Square Support (CS24) or in steeper
cathedral applications where a extra box
length is required, additional insulation may
Figure 10
RAIN CAP (VC)
SILICONE
CAULKING
STORM COLLAR (SC)
RAFTER
SUPPORT
(12) 3" lg. SPIRAL NAILS or
1 1/2” WOOD SCREWS
FLASHING
REFER TO TABLE 6
INSULATION
INTERIOR INSTALLATION WITH CATHEDRAL CEILING
4
Table 5
SQUARE SUPPORT (CS24)
REDUCED CLEARANCE SUPPORT (RCS)
NOTE: ALL DIMENSIONS ARE IN INCHES.
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
FINISH TRIM
(RCS)