Monessen Hearth BWBC500MHB - Manual (Page 15)

61D0087 15
CHIMNEY INSTALLATION
Figure 13 - Standard Roof
FIRESTOP THIMBLE AND THIMBLE EXTENSION
A firestop thimble is required in the chimney installation of all fireplaces safety-certified for installation in manufactured
homes. For shielding purposes, the firestop thimble must pass through the manufactured home ceiling and extend up to the
roof line of the manufactured home. See Figures 13 through 15. When an extension is needed, a thimble extension must
be installed along with the firestop thimble. Models SVTR and SVTE thimble extensions have been safety-certified for use
with this fireplace and should be installed as follows.
1. Lay out, cut and frame a square opening through the ceiling and roof structure at the point where the chimney will pass
through. The SVTR firestop thimble requires a 14½"x14½" square opening. If the chimney is to go through a pitched
roof, the hole in the roof must be rectangular instead of square. A 7½° pitch requires 14½"x14¾" framing. A 15° pitch
requires a 14½"x15" framed opening.
2. Install the SVTR firestop thimble as shown in Figure 13. Nail it securely to the framing members. The firestop thimble
should extend completely through the roof structure to shield combustible construction materials. If the SVTE thimble
extension is needed, it should overlap the firestop thimble a minimum of 1". Screws should be used to secure the thimble
extension to the firestop thimble. See Figure 14.
Figure 14 - Pitched Roof with
Attic Space
Trim off SVTR Firestop
Thimble as Needed to
Seat Flashing
Storm Collar
Flashing
Use Nails to Secure
Firestop Thimble as
Shown
SVTR
Firestop
Thimble
Requires a
14½" x 14½"
Framed
Opening
612 Roof
Flashing
SVTE Thimble
Extension*
Secure SVTE
Thimble
Extension with
Screws as
Shown
* The SVTE Thimble Extension is required …
1. In unvented attic space if attic space exceeds 8"
2. In vented attic space if total chimney height from floor to flue outlet is less than 13½'
Continued
SVTR
Firestop
Thimble