DuraVent DuraTech 10-24 Installation - Manual (Page 10)

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including where the chimney penetrates into
the attic. Figure 6 shows a typical 2-story
installation with an attic.
Note: a Firestop Radiation Shield is not
installed where the chimney penetrates
through the roof. Instead, you will need to
install Roof Radiation Shields (required for
18”-24” diameters only - see Step 7) around
the roof joist members. The Firestop Radiation
Shield is installed on the underside of the
ceiling/floor framing, with the cylindrical “tube”
portion of the shield pointing upward (Fig 7).
Use a minimum of either (1) 8 penny nail or (1)
1-1/4” wood screws per corner. Refer to Table
2 for framing requirements.
7. Install Roof Radiation Shields: Roof
Radiation Shields are required for 18”-24”
diameter chimney installations. Roof Radiation
Shields provide protection for roof framing
members.
Note: Combustible materials will still need to
be a minimum of 2” away from the chimney.
Roof Radiation Shields must be installed with
their face 1/2” off of the roof framing joists (Fig
8). Depending upon the pitch of your roof,
trim the Roof Radiation Shields with tin snips
so they provide complete coverage of the
roof framing exposed to the chimney. Secure
the Roof Radiation Shields to the top of the
framing members using at least (3) nails or
screws for each shield (Fig 8).
8. Assemble Chimney Sections: Lower the
female end of the first Chimney Section in the
Support Box (Fig 9). Sheet metal screws are
not required between the first Chimney Section
and the Support Box. For each additional
Chimney Section use the (6) Sheet metal
screws provided to make a secure connection
between the chimney sections (Fig 9). Do not
penetrate the inner liner of the chimney.
Figure 8
Figure 9
Figure 10
ATTIC
INSULATION
SHIELD
SUPPORT
BOX WITH
SQUARE
TRIM
CHIMNEY
SECTION
SITS INSIDE
SUPPORT
BOX
INSTALL ROOF RADIATION
SHIELDS WITH A 1/2"
CLEARANCE FROM ROOF
JOIST FACE.
NAILS OR SCREWS
ROOF
JOISTS
ROOF
RADIATION
SHIELDS