M&G DuraVent DuraPlus® - Manual (Page 8)

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3. Install Support: Slip the Support Box
,(Figure 5), into the framed opening. It must
extend at least 2 inches below the finished
ceiling. Level the Square Support Box and
nail it to the framing using at least two 8-penny
nails per side. The two Trim Frames are
positioned as shown, and screwed through
the ceiling and into the framing members with
(6) 1-1/4 inch long round-head wood screws.
(Figure 6). The bottom of the Round Support
must also be at least 2 inches below the
finished ceiling. Trim for the Support Boxes
is “U-shaped” . The trim pieces are adjusted
to accommodate the Square Support Box, and
screwed into the framing, using wood screws.
A completed Square Support Box installed in
a cathedral ceiling with the “U-shaped” trim is
also shown in Figure 6. Trim kits are available
in brass, to enhance the appearance of the
various Support Boxes and Trim Frames .
Where the chimney passes through additional
floors and ceilings, install Firestop Radiation
Shields. Where the chimney passes through
an attic, Firestop Radiation Shields and
Insulation Shields must be installed.
4. Frame Openings: Frame openings in
each ceiling or floor above the Support Box.
(Figure 7). These openings are to hold the
Firestop Radiation Shields and Attic Insulation
Shields. Locate each opening by dropping a
plumb bob to the four corners of the opening
below. Maintain the minimum clearances and
Figure 5
ROUND CEILING SUPPORT
SDP-RS
FLAT SUPPORT BOx
SDP-S
Figure 6
WOOD SCREW (6 REq) WOOD SCREW (8 REq)
SUPPORT BOx IN
CATHEDRAL CEILING
WITH TRIM FRAME IN
PLACE
ROUND CEILING
SUPPORT WITH TRIM
PLATES IN PLACE
ATTIC
Figure 7
2 INCH MIN
CLEARANCE
INSIDE OF
ENCLOSURE
FRAMED
ENCLOSURE
MIN OF 2 INCHES
BELOW FINISHED
CEILING
SECOND
ST
OR
Y
CAP SDP-C
STORM COLLAR
SDP-SC
FLASHING
VENTILATED
SDP-SC
CHIMNEY SECTIONS
SDP-P
ATTIC INSULATION
SHIELD SDP-IS
FRAMED
OPENING
SqUARE CEILING SUPPORT
BOx SDP-SB OR ROUND
CEILING SUPPORT SDP-RS
CHIMNEY SECTIONS
SDP-P
FIRESTOP
RADIATION SHIELD
SDP-IS