51
DM 54 Chimney System: Brick Ledge Installation
DM 54 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 54 outer casing and inner liner assembly ap-
proaches the roof penetration set an outer casing block to a level of
approximately 6” below the low side of the roof framing.
(Figure 105)
The alignment tongues on the top of this outer casing block
must be ground off to leave a at contact surface for the brickledge.
Temporarily leave out the inner liner that ts this outer casing block.
Set the Isokern brickledge onto the at 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-specic
support structure design, sizing and load bearing specications.
If short lengths of steel rods are used be sure to properly
lap and wire tie all splices in the rebar. As the reinforcing progress-
es, completely ll the holes with grout. Suitable grout can be a pour-
able mixture of Portland cement and sand or Portland cement, sand
and pea gravel. The rebar must be fully embedded in grout.
Leave enough of the #4 steel reinforcing rod exposed
above the brickledge so that as the stacking of outer casing blocks
continues to termination the reinforcing rods and grout can continue
through the stack. Reinforcing shall continue to chimney termina-
tion.
All DM 54 chimneys that include the DM 54 brickledge
must be reinforced as described above.
CAUTION: When using the Isokern brickledge it is required that
the MAGNUM rebox/smoke dome assembly include the place-
ment of a 4” by 4” by 3/8” minimum steel angle across the rebox
opening. (See page 55 for “Structural Information” for details
regarding specication and placement of steel angles in MAGNUM
replaces.)
Lateral Support for Isokern Brickledge Chimneys:
Once the DM 54 chimney and brickledge are assembled
and after the intended masonry veneer has been installed on the
brickledge, be sure to brace the chimney following the guidelines on
page 45 of this manual for Lateral Support of DM 54 chimneys.
FIGURE 102
FIGURE 103
FIGURE 104
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