M&G DuraVent DuraTech® 5-8 - Manual (Page 20)

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Flashing. Using a Chase Top Flashing allows
for a lower profile for the chimney. The Chase
Top Flashing has an opening that is 3” larger
in diameter than the DuraTech Chimney. If the
Chase Top Flashing can fit over your chase
enclosure as required (Fig 29) then install as
directed, or trim as needed. However, if the
Chase Top Flashing is smaller than your chase
enclosure, you will need to provide a galvanized
sheet capable of covering your chase and
overhanging the sides by 1/2 - 3/4 inch. Attach
the Chase Top Flashing to the galvanized sheet
using appropriate sheet metal screws and non-
hardening waterproof sealant. Use the Chase
Top Flashing Spacers to allow the proper air-gap
clearances on the galvanized sheet. The Chase
Top Flashing Spacers are available to insure
that the proper air-gap is maintained. Figure 29
displays in some detail, how these air gaps are
established using the Spacers and Chase Top
Flashing. Secure the Chase Top Flashing to the
chase using a sufficient number of #8, 1-1/2”
wood screws, being careful to insure the air
Figure 28
Figure 29
ALLOW MIN OF 2 INCHES
AIR SPACE ON ALL SIDES
2 INCHES MIN
2 INCHES MIN
ALLOW 1 INCH AIR
GAP BETWEEN STORM
COLLAR AND CHASE TOP
FLASHING
1/2 INCH AIR SPACE
ESTABLISHED BY
SPACERS
6 INCH MIN CLEARANCE
BETWEEN BOTTOM OF
CAP AND CHASE TOP
FLASHING
1/4 INCH
AIR
SPACE
CHIMNEY CAP
STORM COLLAR
CHASE TOP
FLASHING
CHIMNEY
SECTIONS
SPACER
1/2 INCH
FRAMED CHASE
ENCLOSURE
1/4 INCH