Installation Guide
15
ROOF SUPPORTED 
INSTALLATIONS 
Use only where a leveled Square Support Box 
will extend at least 2 inches below the ceiling 
(on the low side), while the top edge at least 
covers the edge of the roof’s decking material.  
Square Support Boxes are available in 11 
inch, 24 inch, and 36 inch heights. Mobile 
home chimney installations are roof supported, 
and use Ventilated Flashings. Do not seal 
openings. 
Figure 21
2 INCHES MINIMUM 
18 INCHES MINIMUM FOR 
SINGLE-WALL STOVEPIPE
CAP
SDP-C
STORM COLLAR
SDP-SC
VENTILATED FLASHING
SDP-F
CHIMNEY SECTIONS
SDP-P
SQUARE CEILING SUPPORT 
BOX SDP-SB
PUSH SUPPORT BOX UP 
THROUGH ROOF, TRIM 
AND FOLD BACK EXCESS 
AS SHOWN IN FIG. 22
Figure 22
SUPPORT BOX
SDP-SB
1. Place Appliance: Place the appliance in it’s 
proper location, referring to the manufacturer’s 
instructions as to allowable distances from 
combustibles, etc. 
2. Cut Openings: Cut a roof opening directly 
above the appliances’ ue outlet collar, just 
as in a Ceiling-Supported Installation (Steps 1 
thru 5). If a separate ceiling and roof exists, 
as shown in Figure 20, (Low Attic), rst cut 
and frame a ceiling opening as described 
in Ceiling-Supported Installations (Step 2). 
Refer to Table 2 for clearance and framing 
specications. If it is desired to install through 
a cathedral ceiling (Figure 21), then the hole is 
cut in the roof.
3. Install Support Box: Slip the Square 
Support Box into the framed opening so it 
projects at least 2 inches below the nished 
ceiling and rafters, and extends above the 
ceiling to framing or decking materials to 
which it will be nailed. Level the Support Box, 
and slit the corners to the rooine where they 
extend beyond it. Bend the aps (created 
by the slitting) ush with the roof, and nail 
the Support Box to the roof or framing with 
at least two 8-penny nails per side. (Figure 
22). Screw the trim sections into the ceiling. 
(Figure 6).










