Astria.us.com
125160-01_D
24
FIREPLACE INSTALLATION
Continued
Assembly Instructions
MM33/39/44/49
1. Place the hearth base on top of your non-combustible floor or
metal base. For concrete slabs, supporting floor needs to be
rated at ASTM 90.
2. a)
Combustible Floor Installations:
Mix up a batch of mortar
and adhere hearth slabs to the cement board (see Figure 33,
page 22). All-thread rods should stick up through the holes on
the hearth slabs.
b)
Non-combustible Floor Installations:
Draw an outline of
the hearth area based on the dimensions shown in pages 4, 5
and 6. Position Hearth slabs and mark rebar center locations.
Drill 4 inches into concrete slab and secure the 8 pieces of 12
inch rebar with epoxy.
W
28"
(712 mm)
Two 26 ga. Ember
Protectors required
Left Side Hearth 2
nd
Right Side
Hearth 1
st
Model
W
MM33
37"
MM39
43"
MM44
48"
MM49
53"
Apply mortar
between joints
12" Long Rebar
Figure 34 - Positioning Hearth Base For MM33,39,44,49
3. Mix a batch of mortar and prepare Right Side Hearth bottom
surface to be bonded as shown in Figure 35.
4. Align Right Side Hearth to the outline created. The overall width
should allow for an approximate gap of 1/8” between slabs for
the additional mortar to unite the remaining slab. Check for
surface flatness, level if necessary.
1/2
"
away from
edges
1/2
"
mortar bead
typical
Hearth section shown prepared for
Right Side position
Hearth section shown prepared for
Left Side position
Apply mortar bead to
all mating surfaces
Figure 35 - Preparing Hearth Base
Figure 36 - Prepared Hearth Base
5. Apply mortar to the remaining Hearth except this time apply
beading on surface to be facing floor as shown in Figure 36.
6. Before installing side walls, confirm placement of outside air
combustion air access kit (if required), this can be installed
either side depending on which side is accessible to outside
combustion air (all diagrams in this manual show the
combustion air inlet hole on the right side). Prepare side wall
and rear wall mating surfaces with the prepared mortar and
begin assembly.
7. Keep the assembly of the next sections of the firebox side
walls moving up, keeping components moist, mixing mortar
as you need it and threading the mortar appropriately as you
stack each section, one onto the next. Constantly check for
squareness and levelness while building each course of block.
As you complete each section, make certain that you adhere
the mortar at each and every joint.
Side Wall shown prepared for Right Side Air Access.
For Left Side, bead opposite side.
1/2" (13 mm)
away from edges
Figure 37 - Preparing Side and Rear Wall Pieces
