Isokern Standard 36 - Brick Ledge Installation

37
DM Chimney System: Brick Ledge Installation
DM Brick Ledge Installation:
Use of the brick ledge 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
as close to the the low side of the roof framing as possible. (Figure
62)
The alignment tongues on the top of this outer casing
block must be ground off to leave a at contact surface for the
brick ledge. Temporarily leave out the inner liner that ts this outer
casing block.
Set the Isokern brick ledge 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 brick ledge 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 brick ledge. The liner’s top end
will be approximately 3” above the top surface of the brick ledge.
Set the next outer casing block onto the top of the brick ledge 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 brick ledge. The reinforcement
rods must start from a depth of at least 18” below the bottom of the
brick ledge, (In some cases, a minimum recommendation could be
5’).
Consult local structural engineer for proper job-specic
support structure design, sizing and load bearing specications.
If short lengths of steel rods are used be sure to properly
lap and wire tie all splices in the rebar. As the reinforcing
progresses, completely ll the holes with grout. Suitable grout can
be a pourable 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 brick ledge 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
termination.
All DM chimneys that include the brick ledge must be
reinforced as described above.
CAUTION: When using the Isokern brick ledge it is required that
the rebox/smoke dome assembly include the placement of a 4”
by 4” by 3/8” minimum steel angle across the rebox opening.
(See page 40 for “Structural Information” for details regarding
specication and placement of steel angles in replaces.)
FIGURE 61
Brick Ledge