32
Earthcore Industries
MAGNUM Series Fireplace
32
DM Chimney Installation - Offset Run
DM Offset Block
For vertical DM chimney to bypass overhead obstructions, the
Isokern offset chimney block is used. Offset blocks are six inch
(6”) thick, single module chimney components, measuring
21½” wide by 25” long. The 14" hole passes through the block
at thirty (30°) degrees. An offset chimney block can be set as
the first flue component on top of the MAGNUM top plate.
Offset chimney block sequences can be built to shift the
chimney run to the left, right or to the rear of the firebox/
smoke dome assembly.
Offset blocks can be set in a spiraling rotation, thus
moving the chimney to a point that is diagonally away from its
starting point.
Offset blocks require 1½” to combustible framing.
DM Chimney Offset Block Installation and Support
Foundations
Isokern offset chimney blocks are stacked in a stair step
fashion with each successive block overhanging the previous
offset block by three inches (3”), allowing the flue to rise at an
angle of thirty (30°) degrees off of vertical
(Figure 34)
.
Each offset block is to be set fully in a bed of Earthcore
Adhesive, completely sealing each offset block to the
underlying component. When placing the first inner liner on
top of the last offset required, seal the space between the
inner liner and the offset block so that no smoke will be able
to spill through the two joints.
When building offset sequences, it is necessary to
support the third offset block in the sequence and every third
offset block thereafter to footings via concrete block or steel
support columns. When using only one or two offset blocks
no additional support is required. During this building process,
it is important to check the interior flue alignment as each
offset block is set to avoid creating overhanging ledges on
the inside of the flue. Such internal overhangs will inhibit flue
drafting.
Offset sequences are best when built as low as possible
in the chimney run to maximize performance.
If a DM Offset sequence cannot be done at the beginning
of the chimney sequence, you must consult a structural
engineer to ensure proper support is in place for the DM
Chimney Offset.
Plan fireplace and DM chimney systems carefully before
foundations are laid to assure that proper footings are available
to support Isokern offset blocks chimney run.
To calculate the distance of Isokern offset chimney travel
in a straight line to the right, left or to the rear of the firebox/
smoke dome assembly, proceed as follows:
Temporarily dry set a DM outer casing block in its proper
location on top of the completed firebox/smoke dome
assembly as though starting a straight chimney
(Figure 35)
.
FIGURE 34
FIGURE 35
3"
PLUMBLINE
MEASURE
TRAVEL
DISTANCE
OVERHEAD
OBSTRUCTION
TRAVEL
DISTANCE
