Isokern Standard 36 - Flashing & Crown Caps

DM Chimney System: Flashing & Crown Caps
39
Brick ledge Veneer Finish and Flashing Details:
When applying brick, stone or other masonry veneer
to the Isokern brick ledge standard good building practices for
masonry veneer work should govern weather-proong details and
the placement of ashings.
A typical ashing detail would be to eld fabricate an
aluminum or galvanized sheet metal ashing, approximately
thirty-two inches (32”) square with a twenty inch (20”) square hole
in it, to serve as an inner ashing. (Figure 63)
Place the inner ashing on the rst DM outer casing block
that fully clears the roof line. Keep the ashing to about a one-half
inch (1/2”) lap onto the top of the outer casing block. The twenty
inch (20”) square hole in the ashing should t to the outside of
the alignment grooves on top of the DM outer casing. Continue the
DM chimney up to the required termination height.
Once the masonry veneer is in progress the inner ashing
is set into a horizontal joint in the veneer at a level above all
other roof deck ashings, chimney-to-roof ashings and counter
ashings. Weep holes should open to the outer face of the veneer
at vertical mortar joints located at the level of the inner ashing.
(Figure 64)
Where moisture may develop between the DM outer
casing and the chimney veneer, inner ashings as described above
will help to divert such moisture to exterior face of the veneer
by way of the weep holes and thereby keep such moisture from
working its way down between the veneer acing and the DM outer
casing and into the interior of the structure below.
DM Small Crown Cap (Figure 65)
The DM small crown cap is a prefabricated cement
weather cap that measures 26- 1/2” square and 3” thick. The small
crown cap is designed and installed the same as the large crown
cap.
The small crown cap is intended for use where DM
chimneys are to receive thin veneers and cultured stone that do
not require the installation of the Isokern brick ledge. The small
crown cap is also suitable where DM chimneys are to receive
a stucco nish. Other chimney terminations are possible with
DM chimneys. Check local codes for use of custom chimney
terminations and decorative shrouds.
DM Large Crown Cap (Figure 66)
The DM large crown cap is a prefabricated cement
weather cap for masonry veneer chimneys. The large crown cap
measures 37-1/2” square and is 3” thick at its center.
The component has an octagonal hole at its center so that
the top inner liner of the DM chimney stack can pass through it.
The crown cap then sits on the top most DM outer casing block.
To set the large crown cap the last inner liner should be at
least 3” above the last outer casing block in the chimney stack.
Mortar the top of the last outer casing block. Set the large
crown cap over the inner liner and onto the top of the last outer
casing in the stack.
Caulk or mortar the joint between the octagonal liner and
the crown cap where the liner comes through the top surface of the
large crown cap.
FIGURE 66
INNER
FLASHING
SMALL
CROWN CAP
LARGE
CROWN CAP
FIGURE 64
FIGURE 63
FIGURE 65