58
Specialty Applications - Two Story Stacked Installations
General Information:
To install one MAGNUM fireplace and DM 54
chimney system above another, as in a two story stacked
installation, both the upper and lower fireplace installations
require a concrete slab that is supported down to footings via
concrete or steel support structure.
Frequently in two story stacked installations the lower
unit is supported by a slab-on-grade (as in a basement), whereas
the upper unit is a typical off-grade support slab.
The off-grade slab for the upper unit must be built with sufficient
width in order to accommodate the width of the upper fireplace
plus the width of the by-passing chimney system rising from the
lower unit. (Figure 121)
The slab for the lower unit will need to be built with
enough width to provide support for the lower fireplace unit
plus the bearing surface for the support columns needed to carry
the offset chimney sequence of the lower system. (Figure 121)
Floor-to-Floor Height Considerations:
In order for the lower fireplace installation to have
enough overhead height clearance for its chimney to rise at a
thirty degree (30°) angle of offset (maximum angle of offset as
allowed by code) and bypass to one side of the firebox in the
upper location there are minimum required floor-to-floor height
dimensions. (See chart, page 54, Dimension “F”)
The minimum floor-to-floor height required for an
installation is determined by calculating the total horizontal
distance the lower flue must travel to the left or right for it to
bypass to one side of the upper fireplace
(see calculating offsets on page 41).
The total amount of horizontal chimney offset travel
distance will be determined by two factors:
1. The width dimension of the upper unit; and
2.The horizontal distance between centerlines of the
proposedupper and lower units.
Example:
If the upper fireplace and the lower fireplace sit on the
same centerline then the required floor-to-floor dimension is
at a maximum (See Figure 122 and chart, page 50 dimension,
column “F”.)
For every 3” of horizontal distance separating the
centerlines of the upper and lower units the overall height of the
offset sequence is reduced by one offset block or by 6”.
Notes:
A raised hearth at the lower fireplace will increase
the minimum floor-to-floor height requirement by the height
dimension of the raised hearth.
In the interest of clarity the drawing on pages 58 & 59
(Figure 121 & 122) of the offset chimney sequence does not
show the offset block support columns as required for offset
sequences and as described on page 47 of this manual.
FIGURE 121
