BRICK LEDGE
ISOKERN
BRICKLEDGE
44
DM Chimney System: DM Brick Ledge
DM Brick Ledge:
The DM brickledge is a 3” thick, 32-1/2” square, steel
reinforced, concrete and pumice slab (Figure 91). It provides
a 5” ledge at all four sides of the outer casing block and is
designed to support masonry veneers to DM chimneys starting
below the rafters and continuing to termination. (Figure 92)
The component is cast with an octagonal hole in its
center so that the DM octagonal inner liner can pass through it.
The brickledge has four 2-1/2” holes through it that
align with the hole in each of the four corners of the DM outer
casing block. These four holes are provided for reinforcement
of the chimney stack by the insertion of #4, minimum, steel
reinforcing rods and subsequent grouting. (Figure 93)
The brickledge is intended for use in chimneys that
rise through the roof only where all four sides of the chimney
are bounded by the roof.
WARNING:
To maintain structural performance the DM
brickledge must not be cut or altered in any way.
DM Brick Ledge Installation:
Use of the brickledge will require a roof framing
rough opening of at least 34” in width. The required opening
dimension along the length of the rafter, where the chimney is
to penetrate the roof line, will increase above 34” relative to the
pitch of the roof.
As the DM outer casing and inner liner assembly
approaches the roof penetration set an outer casing block to
a level of approximately 6” below the low side of the roof
framing. (Figure 94)
The alignment tongues on the top of this outer casing
block must be ground off to leave a flat contact surface for the
brickledge. Temporarily leave out the inner liner that fits this
outer casing block.
Set the Isokern brickledge onto the flat top surface of
the outer casing in a full bed of Earthcore Mortar. Be sure to
align the four 2-1/2” holes in the brickledge with the matching
holes in the outer casing block below it. Return to setting the
next inner liner in the sequence. This inner liner comes up from
below and passes through the octagonal hole in the brickledge.
The liner’s top end will be approximately 3” above the top
surface of the brickledge. Set the next outer casing block onto
the top of the brickledge in a bed of Earthcore Mortar.
Insert one piece of #4 (minimum) steel reinforcing
rod into each of the four 2-1/2” holes in the brickledge. The
reinforcement rods must start from a depth of at least 18”
below the bottom of the brickledge. (In some cases, a minimum
reccommendation could be 5’)
Consult local structural engineer for proper job-
specific support structure design, sizing and load bearing
specifications for the Magnum Model 86072.
FIGURE 91
FIGURE 93
FIGURE 92
Summary of Contents for Magnum 86072-60
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