FireRock FIREROCK VENT FREE User manual

IMPORTANT: This manual contains product usage guidelines infield application rules installation steps and operating and
maintenance instructions for the FireRock Vent Free/SeeThrough Vent Free preengineered masonry fireplace kit This manual
should become the property of and be reviewed by all current and future users of this product It is the responsibility of the general
contractor and the installer to ensure that the instructions set forth in this manual are followed exactly It is also the responsibility
of the general contractor to provide adequate clearance to combustibles see page  from all fireplace surfaces as specified herein
Before installing this product please consult with local building and zoning authorities regarding the need for proper permitting
IMPORTANT: Read the entire manual before beginning construction.
Contents of this manual may change without prior notification
MANUFACTURING:
 Avenue C
Birmingham AL 
ADMINISTRATIVE:
 st Ave N #
Birmingham AL 
PHONE   FAX  TOLLFREE  
LISTED MASONRY FIREPLACE SYSTEM
MODEL FIREROCK VENT FREE/SEETHROUGH VENT FREE
” ” ” ” MODULAR FIREPLACE
ANSI Z21.91 COMPLIANT
VENT FREE/SEE-THROUGH VENT FREE FIREPLACE
INSTALLATION, SPECIFICATION AND OPERATION MANUAL
If the information in this manual including installation instructions is not followed exactly a fire or explosion may result
causing property damage personal injury or loss of life
Installer: Leave this manual with the appliance.
Consumer: Keep these instructions for future use.
For use only with a listed gasfired unvented decorative room heater not to exceed  BTU/H Do not build a wood fire

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TABLE OF CONTENTS
Important Safety Information 
Materials and Equipment List 
Intended Use Statement 
Installation Considerations 
Warnock Hersey Listing Labels 
Fireplace Dimensions 
Clearance to Combustibles 
Rough Framing Dimensions 
Fireplace Installation 
Foundation 
Mixing and Applying Mortar 
Firebox Assembly 
Placing the Top Plate 
Firebrick Installation 
Typical Gypsum Board Application 
Operating Instructions 
Vent Free Parts Dimensions 
SeeThrough Vent Free Parts Dimensions 
Terms and Conditions 




















4
IMPORTANT SAFETY INFORMATION
The FireRock Vent Free/SeeThrough Vent Free fireplace is a modular system designed to be assembled in field using FireRock
Adhesive Mortar Each component is designed for a specific part of the firebox smoke chamber and flue design and therefore only
one means of assembly is possible A minimum  ¼” thick firebrick lining is required compliant with ASTM 
Any application other than the “intended use” stated herein is in violation of the manufacturer’s instructions and is hereby
prohibited Such violations may cause immediate hazard property damage or loss of life and will void all liabilities to the
manufacturer and will void all warranties explicit or implied
Read the installation and operating instructions carefully and in full to be sure you understand them prior to installation If the
information in this manual including installation instructions is not followed exactly a fire or explosion may result causing
property damage personal injury or loss of life
 Check local building codes pertaining to fireplaces and fireplace installation All installations must comply with local
regional state and national building codes and regulations In the absence of local codes installation must comply with the
National Fuel Gas Code ANSI Z223.1/NFPA 54
 Maintain the stated minimum clearance to combustibles see page  and do not violate any specific installation
requirement
 Do not pack required air spaces with insulation or other materials
 Foundations and footings must meet local building code and be approved by the local building authority For any
foundation design and load requirements check with a structural engineer
 Do not use a fireplace insert or other product not specified for use with a fireplace with the reflective properties of this
product
 Do not build a wood fire in the FireRock Conventional Vent Free or SeeThrough Vent Free fireplace These fireplaces are
for use with decorative type unvented room heaters only
 The Conventional Vent Free fireplace has not been tested for use with doors To reduce the risk of fire or injury do not
install doors on this model
 Fireplace screens or equivalent means designed to prevent unintentional access into the firebox interior must be provided
 Do not burn construction debris of any kind in this fireplace
 Overfiring can permanently damage the system
 Only unvented gas logs that are listed by ANSI Z can be used in this fireplace
NOTE: This is important safety information for the installation of this fireplace
For safety information regarding the operation of this fireplace see pages 
Carefully review the instructions supplied with the decorative type unvented room heater for the minimum fireplace size
requirement Do not install an appliance in this firebox unless this firebox meets the minimum dimensions required
for the installation

5
MATERIALS AND EQUIPMENT LIST
NOTE: Some of the components of this
fireplace are extremely heavy and should not be
lifted by one person Because of this realize that
building this fireplace is at minimum a twoman
job
REQUIRED MATERIALS & EQUIPMENT
 Clean water
 Trowel
  gallon bucket
 Level
 Plastic shims
 FireRock Adhesive Mortar
 Firebrick
 ANSI Z listed gas log set
max  BTU
See pages 26-27 for component specifications
30” 36” 42” 48”
” Base plate 
” Base plate 
” Base plate 
” Base plate 
Firebox side    
” Top Plate 
” Top plate 
” Top plate 
” Top plate 
TOTAL 8 8 8 8
SEE-THROUGH VENT FREE
MASONRY FIREPLACE SYSTEM COMPONENTS
30” 36” 42” 48”
” Base plate 
” Base plate 
” Base plate 
” Base plate 
Firebox side    
Back wall ” Courses  &  
Back wall ” Course 
Back wall ” Course 
Back wall ” Courses  &  
Back wall ” Course 
Back wall ” Course 
Back wall ” Courses  &  
Back wall ” Course 
Back wall ” Course 
Back wall ” Courses  &  
Back wall ” Course 
Back wall ” Course 
” Top Plate 
” Top plate 
” Top plate 
” Top plate 
TOTAL 14 14 14 14
VENT FREE
MASONRY FIREPLACE SYSTEM COMPONENTS
See page 23-25 for component specifications
*The Conventional Vent Free fireplace can also accommodate a straight back wall.

6
INTENDED USE STATEMENT
NOTE: Illustrations in this manual are not to scale and are intended to show “typical” installations The FireRock ”
Conventional Vent Free model is shown throughout this manual unless otherwise noted Nominal dimensions are given for design
and framing reference only since actual installations may vary due to job specific designs and preferences Always maintain the
stated minimum clearance to combustibles and do not violate any specific installation requirement
The fireplaces are tested and listed by Intertek Testing Service to ANSI Z
The FireRock Conventional Vent Free and SeeThrough Vent Free fireplaces are designed to burn gas only They cannot be used
as a wood burning fireplace Only unvented gas logs that are listed by ANSI Z can be used in this fireplace Do not use wood
or other solid fuel in the FireRock Conventional Vent Free or SeeThrough Vent Free fireplaces
Burning some fuels can be hazardous due to the possibility of producing carbon monoxide which is both invisible and odorless
Overexposure to carbon monoxide can lead to illness and death It is strongly recommended to install smoke and carbon
monoxide detectors wherever fireplaces are in use
This fireplace is intended for use as a supplemental heat source only and is not intended for heavy use as a primary heating system
Overfiring abusive burning or mistreatment will void any warranty claims
Do not use a fireplace insert or other product not specified for use with a fireplace with the reflective properties of this product
Any fireplace insert must be approved in writing by FireRock Products LLC Failure to heed this warning could result in failure of
this product and/or the insert product
Always obtain necessary permits from proper authorities in local jurisdictions and comply with all local building codes
All work performed on near and adjoining the fireplace and chimney installation must meet or exceed the specifications and
requirements in this manual and the prevailing local building code Subsequent renovations and/or additions of cabinets and
storage spaces in the enclosure surrounding the fireplace are also limited to the specifications in this manual and to the prevailing
local building code
Modifications to fireplace components not mentioned in this manual may void warranty claims listing and approvals and could
result in an unsafe and potentially dangerous installation Alterations to the firebox are allowed with prior written approval and
instruction from FireRock The installer indemnifies will defend and hold harmless the manufacturer from all claims and losses
and under no circumstances will manufacturer be liable for damages of any kind or nature whether foreseeable or not arising out
of or relating to any modifications of the fireplace by the installer
The Conventional Vent Free fireplace has not been tested for use with doors
The FireRock Conventional Vent Free and SeeThrough Vent Free fireplaces are approved for Indoor and Outdoor use Maintain
stated clearance to combustibles for indoor and outdoor use

7
INSTALLATION CONSIDERATIONS
A. COMBUSTION AIR
Always ensure that an adequate supply of replacement air from outside of the house is accessible to the fire to support normal
combustion For more information about adequate combustion and ventilation air refer to the unvented room heater’s installation
instructions
B. BROKEN COMPONENTS
Components that become broken due to poor handling or shipping should be mortared back together providing the breaks or
cracks are clean and original alignment and dimension can be maintained Components broken into multiple pieces or fragments
must be discarded and replaced When in doubt about a component’s usability consult your FireRock distributor or authorized
FireRock representative for advice You may also call the FireRock Technical Support Desk tollfree at 
C. GAS LINE APPLICATIONS
The FireRock fireplace may be drilled through with an ordinary masonry drill bit to accommodate a natural gas connection
This natural gas connection may be used to  incorporate an automatic shutoff device and/or  comply with the Standard for
Decorative gas appliances for installation in Vent Free Fireplaces ANSI Z The decorative gas appliance should be installed
in accordance with the National Fuel Gas Code ANSI Z
HINTS
 If this is your first FireRock installation it would only take a few extra minutes to “dry stack” erect without mortar your
firebox to gain a better understanding of how the components go together Then disassemble and erect using FireRock
Adhesive Mortar
 Use a level to ensure all components are level by course and plumb as you erect your fireplace and chimney
 Ensure your base plate is level and at a proper elevation so the finished hearth height including firebrick lining is correct
in relationship to your finished floor height
 Realize that this is at minimum a twoman job Some of these components are too heavy for one person to lift
5. Always install in accordance with local codes.
Only unvented gas logs that are listed by ANSI Z can be used in this fireplace This fireplace has not been tested with a
vented gas log set To reduce the risk of fire or injury do not install an unvented gas log set into this fireplace

8
LISTED VENTLESS FIREBOX ENCLOSURE
MODEL FireRock 30 VF 36 VF 42 VF 48 VF
CERTIFIED TO ANSI Z21.91-2017
FOR USE WITH APPROVED ANSI Z21.11.2
DECORATIVE TYPE UNVENTED ROOM HEATERS
SEE FIRE ROCK’S INSTALLATION AND
OPERATING INSTRUCTIONS FOR THIS MODEL
REFER TO THE INTERTEK DIRECTORY OF BUILDING PRODUCTS
(HTTPS://BPDIRECTORY.INTERTEK.COM) FOR DETAILED INFORMATION.
CLEARANCE TO COMBUSTIBLES
MANUFACTURED BY: FIRE ROCK PRODUCTS, LLC; 3620 AVENUE C; BIRMINGHAM, AL 35064
WHI-
UNIT TO FLOOR 0 IN.
UNIT TO SIDE FRAMING 0 IN.
UNIT TOP AT FRONT TO FRAMING 3 IN.
UNIT OPENING TO ADJACENT WALL 6 IN.
UNIT TO BACKWALL 0 IN.
UNIT TOP AT REAR TO FRAMING 0 IN.
UNIT OPENING TO MANTLE 12 IN.
SIZE: 3-3/8” X 5-7/8”
NO HOLES OR ADHESIVE
FIREPLACE SCREENS, OR EQUIVALENT MEANS DESIGNED TO PREVENT UNINTENTIONAL ACCESS
INTO THE FIREBOX INTERIOR, MUST BE PROVIDED. FOR USE WITH LISTED ANSI Z21.11.2 UNVENTED
DECORATIVE ROOM HEATERS NOT TO EXCEED 40,000 BTU/HR (11 723 W).
W/N 13351
PLEASE PROOF COMPLETELY -
SIGN AND RETURN IF OKAY TO PRINT.
THE NAMEPLATE WILL PRINT
EXACTLY AS IT APPEARS HERE.
DO NOT SIGN IF CHANGES WERE MADE.
A NEW PROOF WILL NEED TO BE SENT.
THANK YOU
X
WARNOCK HERSEY LISTING LABELS
LISTED VENTLESS SEE-THRU (2 SIDED) FIREBOX ENCLOSURE
MODEL FireRock 30 VF-ST 36 VF-ST 42 VF-ST 48 VF-ST
CERTIFIED TO ANSI Z21.91-2017
FOR USE WITH APPROVED ANSI Z21.11.2 DECORATIVE TYPE UNVENTED ROOM HEATERS
SEE FIRE ROCK’S INSTALLATION AND OPERATING INSTRUCTIONS FOR THIS MODEL
REFER TO THE INTERTEK DIRECTORY OF BUILDING PRODUCTS
(HTTPS://BPDIRECTORY.INTERTEK.COM) FOR DETAILED INFORMATION.
CLEARANCE TO COMBUSTIBLES
FIREPLACE SCREENS, OR EQUIVALENT MEANS DESIGNED TO PREVENT UNINTENTIONAL ACCESS
INTO THE FIREBOX INTERIOR, MUST BE PROVIDED. FOR USE WITH LISTED ANSI Z21.11.2 UNVENTED
DECORATIVE ROOM HEATERS NOT TO EXCEED 40,000 BTU/HR (11 723 W).
MANUFACTURED BY: FIRE ROCK PRODUCTS, LLC; 3620 AVENUE C; BIRMINGHAM, AL 35064
WHI-
UNIT TO FLOOR 0 IN.
UNIT TO SIDE FRAMING 0 IN.
UNIT TOP AT FRONT TO FRAMING 3.5 IN.
UNIT TO BACKWALL N/A
UNIT TOP AT REAR TO FRAMING 0 IN.
UNIT OPENING TO MANTLE 12 IN.
PLEASE PROOF COMPLETELY -
SIGN AND RETURN IF OKAY TO PRINT.
THE NAMEPLATE WILL PRINT
EXACTLY AS IT APPEARS HERE.
DO NOT SIGN IF CHANGES WERE MADE.
A NEW PROOF WILL NEED TO BE SENT.
THANK YOU
X
W/N 14915
SIZE: 3.2” X 5.875”
PRINTS BLACK LETTERS ON ALUMINUM
NO HOLES OR ADHESIVE

9
FIREPLACE DIMENSIONS
DIMENSION ” ” ” ”
AOVERALL WIDTH ” ” ” ”
BOVERALL DEPTH ” ” ” ”
CFIREBOX HEIGHT ” ” ” ”
DOPENING WIDTH ” ” ” ”
EOPENING HEIGHT 34.5” 34.5” 34.5” 34.5”
FWIDTH AT FIREBOX CENTER ” ” ” ” A
F
D
EC
B
FIGURE 1.2
SEE-THROUGH VENT FREE FIREPLACE
*before firebrick lining
SEE-THROUGH VENT FREE FIREPLACE
DIMENSION ” ” ” ”
AOVERALL WIDTH ” ” ” ”
OVERALL DEPTH ” ” ” ”
CFIREBOX HEIGHT ” ” ” ”
DOPENING WIDTH ” ” ” ”
EOPENING HEIGHT 33” 33” 33” 33”
FFIREBOX DEPTH ” ” ” ”
GWIDTH AT REAR ” ” ” ”
*before firebrick lining
A
G
D
EC
F
FIGURE 1.1
VENT FREE FIREPLACE
VENT FREE FIREPLACE

10
CLEARANCE TO COMBUSTIBLES
Opening to Side wall ”
Opening to Combustible
Mantle with ” Depth ”
Unit to Floor ”
Unit Top Side Framing ”
Unit Top at Front to Framing ”
Unit Top at Rear to Framing ”
MANTLE
SIDEWALL
TILE/MARBLE 12”
6”
FIGURE 2
Failure to maintain stated minimum clearance to combustibles may result in a fire or explosion causing property damage
personal injury or loss of life
Do not pack required air spaces with insulation or other materials Using insulation or other materials in required air spaces
may result in a fire or explosion causing property damage personal injury or loss of life
NOTE “Combustibles” are defined as “normal construction materials” and are considered to be wood framing materials particle
board mill board plywood subflooring plywood paneling wood flooring and drywall

11
ROUGH FRAMING DIMENSIONS
The numbers listed are the framing dimensions recommended by FireRock which add ½” of air space to the required clearances
Always maintain the stated minimum clearance to combustibles for this unit
For ease of installation it is recommended to not install framing header until after firebox is installed
Rough framing dimension “A” includes the  ³₄” thick base plate Dimension “A” should be reduced by  ³₄” if the base plate is
eliminated to create a “flush hearth” A raised hearth requires additional rough opening height for dimension A equal to the height
of the raised hearth detail
A
B
C
FIGURE 3
Failure to maintain stated minimum clearance to combustibles on page  may result in a fire or explosion causing property
damage personal injury or loss of life
VENT FREE FRAMING
” ” ” ”
A44” 44” 44” 44”
B29” 29” 29” 29”
C39” 45” 51” 57”
SEE-THROUGH VENT FREE FRAMING
” ” ” ”
A44.5” 44.5” 44.5” 44.5”
B29” 29” 29” 29”
C39” 45” 51” 57”

12
The FireRock Vent Free/SeeThrough Vent Free fireplace
may be erected directly on a noncombustible base
If the design calls for the enclosure to be installed on
carpeting tile or a combustible material other than wood
flooring the enclosure should be installed on a metal or
wood panel extending the full width and depth of the
enclosure
Never place the vent free fireplace on a combustible floor
without the base plate
FIREPLACE INSTALLATION
STEP 1: FOUNDATION
FIGURE 4.1
VENT FREE FIREPLACE ON WOOD FLOORING
FIGURE 4.2
VENT FREE FIREPLACE ON COMBUSTIBLE MATERIAL
OTHER THAN WOOD FLOORING

13
FIREPLACE INSTALLATION
STEP 2: MIXING AND APPLYING MORTAR
FIREROCK ADHESIVE MORTAR
FireRock Adhesive Mortar must be used when building the
FireRock fireplace for your FireRock warranty to be valid
Use of other mortar will void your FireRock warranty
This mortar is available from your FireRock dealer or
distributor This specially formulated mortar is a low
sand polymer modified with heat resistant additives and
is designed to work as a “glue” rather than a typical joint
provider
MIXING THE MORTAR
Mix FireRock Adhesive Mortar with clean water
according to the instructions on the bag until it results in
a “toothpaste” consistency free of lumps or dry pockets
Be sure it is not too thin or runny to ensure maximum
strength Use only clean water when mixing FireRock
Adhesive Mortar Do not use spirits or antifreeze agents
Do not apply if temperatures are below  F or will be
within a  hour period
APPLYING THE MORTAR
It is appropriate to use a trowel or grout bag to apply the
mortar to firebox and smoke chamber joints These joints
should be COMPLETELY COVERED BY ¹₂”  ” OF
MORTAR Figure  and the components stacked so
as to result in a ¹₁₆” to ¹₈” joint The excess mortar should
push ooze out and be scraped away
BUTTERING THE JOINTS
At each level of the firebox smoke chamber and masonry
chimney it is important to go back and “butter” all joints
This procedure involves a final smoothing of any excess
mortar inside and out sealing all joints and ensuring a “no
leak” installation Figure 
FIGURE 5.1
SIDE BLOCK WITH MORTAR APPLIED TO TOP FACE
FIGURE 5.2
FIREBOX WITH BUTTERED JOINTS

14
FIREPLACE INSTALLATION
STEP 3: FIREBOX ASSEMBLY
BASE PLATE
The base plate must be placed on a level surface It is very
important that your base plate be square to the room
properly centered and level Mark out the position of the
base plate on the supporting floor system Apply a layer of
mortar to the area and set the base plate Figure 
FLUSH HEARTH (FIGURE 6.2)
If the design calls for a flush hearth you can omit the base
plate from the assembly instructions and build the side
walls directly on the concrete pad or slab In the event you
opt not to use the base plate carefully chalk lines where the
base plate would be to ensure proper placement of your
firebox
With a flush hearth the firebrick floor of the firebox will be
applied directly to the concrete slab or pad This makes the
finished firebrick floor approximately  ¹₂” above the top of
the slab or pad
RAISED HEARTH (FIGURE 6.3)
If the design calls for a raised hearth then the base plate
should be set on a noncombustible platform that is built up
to the desired hearth height
When calculating the hearth height be sure to account for
both the  ³₄” base plate and  ¹₂” thick firebrick floor in
addition to the height of the platform
NOTE: If installing a SeeThrough Vent Free fireplace skip
to page  for specific assembly instructions The base plate
will be installed upside down for this assembly
FIGURE 6.1
BASE PLATE
FIGURE 6.2
FLUSH HEARTH
FIGURE 6.3
RAISED HEARTH
If installing on a combustible floor the base
plate must be used Installing this fireplace on a
combustible floor without the base plate may result
in a fire or explosion causing property damage
personal injury or loss of life

15
FIREPLACE INSTALLATION
STEP 3A: VENT FREE FIREBOX ASSEMBLY
BACK WALL AND SIDE BLOCKS
Side blocks and back blocks are next Completely cover
each component with mortar ¹₂”  ” thick where it will lie
or butt up against another component You will begin by
placing a back block on the base plate Figure  Next
place the corresponding side blocks Figure  again
completely covering each edge of a component that butts
up to another component including the base plate with
¹₂”  ” of mortar Use your level to ensure level and plumb
placement of each component
Continue to build each course of the firebox making sure
all surfaces are plumb and level and firebox position is
correct Figure 
NOTE: The Conventional Vent Free model can be built
with a straight or an angled back wall The angled back wall
is shown throughout the assembly instructions
If the unit has an angled back wall the first  courses of
the firebox use identical straight back blocks followed by
angled back wall pieces for course  Figure  and course
 Figure  The back wall pieces can only be positioned
one way
If the unit has a straight back wall all  back blocks will be
identical
Butter all joints inside and out see page 
LEVELING AND ALIGNING COMPONENTS
It is important that each course of the firebox is level
and flush with adjoining components FireRock mortar
is not intended to create a mortar joint of any thickness
for leveling purposes Leveling and alignment adjustments
should be made by the use of small shims Be sure to re
mortar any gaps resulting from the shims to maintain a
leakfree seal
FIGURE 6.5
1 COURSE
FIGURE 6.4
BASE PLATE + 1 BACK BLOCK
FIGURE 6.7
FULLY ASSEMBLED FIREBOX
FIGURE 6.6
3 COURSES WITH ANGLED BACK WALL
NOTE: If you are installing a SeeThrough Vent Free Fireplace see Step B page  for more specific assembly instructions

16
FIREPLACE INSTALLATION
STEP 3B: SEE-THROUGH VENT FREE FIREBOX ASSEMBLY
NOTE: If you are installing a Conventional Vent Free Fireplace see Step A page  for more specific assembly instructions
SIDE BLOCKS
Place a side block Figure  completely covering
each edge of the component that butts up to another
component including the base plate with ¹₂”  ” of
mortar Use your level to ensure level and plumb placement
of each component
NOTE: The SeeThrough Vent Free Fireplace can be built
with the angled sides of the side wall facing in Figure 
or facing out Figure 
Continue to build each course of the firebox making sure
all surfaces are plumb and level and firebox position is
correct Figure 
Butter all joints inside and out see page 
LEVELING AND ALIGNING COMPONENTS
It is important that each course of the firebox is level
and flush with adjoining components FireRock mortar
is not intended to create a mortar joint of any thickness
for leveling purposes Leveling and alignment adjustments
should be made by the use of small shims Be sure to re
mortar any gaps resulting from the shims to maintain a
leakfree seal
FIGURE 6.8
BASE PLATE + 1 SIDE BLOCK
FIGURE 6.9
STANDARD INSTALLATION - SIDE BLOCKS FACING INWARD
FIGURE 6.10
ALTERNATE INSTALLATION - SIDE BLOCKS FACING OUTWARD
FIGURE 6.11
FULLY ASSEMBLED FIREBOX

17
FIREPLACE INSTALLATION
STEP 4: PLACING THE TOP PLATE
The final component of the fireplace is the top
plate Completely cover the tops of the firebox sides
and back block with ¹₂”  ” of mortar before placing
this final component and be sure it is level frontto
back and sidetoside
NOTE: The top plate should be placed so that the
raised portion is facing down leaving the top flat
Figure 
“Butter” all joints to ensure a noleak seal
FIGURE 6.12
PLACING THE TOP PLATE

18
FIREPLACE INSTALLATION
STEP 7A: FIREBRICK INSTALLATION - VENT FREE FIREPLACE
A  ¼” minimum firebrick ASTM  lining is required
to meet the standard Thicker firebrick compliant with
ASTM  may be used as an option if desired The
same FireRock Adhesive Mortar used for the firebox and
chimney should be used to affix the firebrick to the inner
wall of the firebox
Follow the installation instructions below when laying your
firebrick
FIREBRICK INSTALLATION
 Mix mortar according to package instructions
 Apply a skim coat of mortar approximately ¹₁₆”
thick to the back wall to remove air gaps and
provide added heat protection
 Using a trowel apply mortar to the face and sides of
the firebrick to achieve a joint thickness of ¹₁₆”  ¹₈”
unless otherwise noted
 Start applying the firebrick at the front edge of the
floor and work your way back leaving approx ½”
gap off the back and side walls Figure   this
space allows for heat expansion and is to be left
empty of mortar For the floor only FireRock
recommends a brick to brick joint
NOTICE: Failure to leave an expansion gap can
result in firebrick cracking
 Apply firebrick to the back wall Cover the
expansion gap on the floor with the overlap of
brick leaving it free of mortar Leave a ¹₂” expansion
along both side walls Figure 
 Apply firebrick to the side walls starting at front of
box and moving back covering the expansion gaps
along the floor and back wall with the overlap of
brick but leaving it free of mortar Figure 
FireRock makes no claims as to the performance of
firebrick or firebrick mortars except those manufactured
by FireRock It is typical for heat stress cracks to appear
in the firebricks after use The National Fire Protection
Association Standard  says your fireplace and flue
should be inspected at least once a year
FLOOR WITH 1/2” EXPANSION GAP
ALONG BACK AND SIDE WALLS
FIGURE 8.1
FLOOR & BACK WALL WITH 1/2”
EXPANSION GAP ALONG SIDE WALLS
FIGURE 8.2
FULLY BRICKED FIREBOX
COVERING EXPANSION GAPS
FIGURE 8.3

19
FIREPLACE INSTALLATION
STEP 7B: FIREBRICK INSTALLATION - SEE-THROUGH VENT FREE FIREPLACE
A  ¼” minimum firebrick ASTM  lining is required
to meet the standard Thicker firebrick compliant with
ASTM  may be used as an option if desired The
same FireRock Adhesive Mortar used for the firebox and
chimney should be used to affix the firebrick to the inner
wall of the firebox
Follow the installation instructions below when laying your
firebrick
FIREBRICK INSTALLATION
 Mix mortar according to package instructions
 Using a trowel apply mortar to the face and sides of
the firebrick to achieve a joint thickness of ¹₁₆”  ¹₈”
after the brick is stuck to inner wall of the firebox
 Start applying the firebrick at the front edge of the
floor and work your way back leaving approx ½”
gap off the side walls Figure   this space allows
for heat expansion and is to be left empty of mortar
NOTICE: Failure to leave an expansion gap can
result in firebrick cracking
 Apply firebrick to side walls starting at front of
box and moving back covering the expansion gaps
along the floor with the overlap of brick but leaving
it free of mortar Figure 
FireRock makes no claims as to the performance of
firebrick or firebrick mortars except those manufactured
by FireRock It is typical for heat stress cracks to appear
in the firebricks after use The National Fire Protection
Association Standard  says your fireplace and flue
should be inspected at least once a year
FLOOR WITH 1/2” EXPANSION
GAP ALONG SIDE WALLS
FIGURE 8.4
FULLY BRICKED FIREBOX
COVERING EXPANSION GAPS
FIGURE 8.5

20
TYPICAL GYPSUM BOARD APPLICATION
Failure to maintain stated minimum clearance to combustibles on page  may result in a fire or explosion causing property
damage personal injury or loss of life
FIGURE 9.1
SEE-THROUGH VENT FREE FIREPLACE
VENT FREE FIREPLACE
FIGURE 9.2