Masonry Fireplace Accessories

Firebrick and Mortar

Firebrick used must comply with ASTM standards C1261 and C27 and meet or exceed the requirements of local, national, and international building codes regarding fireplace and chimney construction and the National Fire Protection Association NFPA-211. A compliant firebrick lining is 1 1/4" or 2 1/2" thick. Although you can use either firebrick thickness to line the sides, back and floor of the firebox, FireRock recommends using the 2 1/2" thick firebrick to line the floor.

FireRock Mortar must be used to install the firebox and may also be used to install the firebrick. Substitutions in the firebox will result in a non-compliant unit and will invalidate FireRock warranty.

  • Available colors: Red and Buff
  • Full Firebrick: 4" (W) x 9" (L) x 2 1/2" (D)
  • Split Firebrick: 4" (W) x 9" (L) x 1 1/4" (D)
  • Soaps (Buff color only): 2 1/4" (W) x 9" (L) x 1 1/4" (D)
  • Popular firebrick patterns include: Running Bond, Stacked Bond, Basket Weave, Full Herringbone, Split Herringbone
FireRock firebrick in buff and red

Bricking Flange

FireRock’s Bricking Flange can be used in conjunction with the Solid Block Chimney so that a masonry veneer can be added above the roofline without building a special support structure through the house. This steel-reinforced masonry ledge also supports a traditional chimney pot or other decorative masonry finish.

This accessory is perfect for use in neighborhoods with strict building covenants because the chimney exterior can be finished with the same material as the rest of the home.

  • Measurements: 32" x 32" x 4"
  • Supports up to 20 ft of vertical brick
  • Installed in the chimney stack approx. 12” below the low side of the roofline inside the attic space

Important: Please consult local building codes for specifics regarding masonry above the roof.

Masonry Fireplace Accessories - Bricking Flange

Offset Blocks

Use FireRock Offset Blocks when design paramerers do not allow for a vertical chimney installation. Offset Blocks allow you to move the chimney path so that objects, such as another fireplace, may be positioned above the firebox.

A non-combustible column under every fifth block must support the Offset Blocks in a series. Offset blocks are stacked in series with each one providing a maximum offset 2 5/8″. Offset direction may be left, right, back, or in a spiral pattern for “twisting” flues.

  • Offset Block Height:4"
  • Additional Measurements: 24" (W) x 28" (L)
  • Maximum Horizontal Distance (or max offset): 40"
  • Clearances: 1" clearance to combustibles
  • Each block has an angled flue hole that provides a 30 degree vertical passageway for flue gases
  • Good for moving the chimney outside the wall of the home to avoid interference with the upstairs floor plan

Important: Please consult local building codes for specifics regarding all masonry fireplace applications.

Masonry Fireplace Accessories - Offset Blocks

Metal Chimney System

As an alternative to the Solid Block Chimney, all FireRock fireplace units are designed to accommodate metal chimney systems. Theses metal components are light weight and allow for more flexibility in the location of your fireplace.

FireRock distributes M&G Duravent, DuraChimney II UL103 (air-cooled applications). The double-wall, air-cooled design allows the chimney to expand both radially and lengthwise under high temperatures. 

  • Height subject to job site specifications.
  • Clearance to Combustibles: 2" around metal chimney (M&G Duravent)
  • For use with masonry fireplaces which burn wood, oil, coal, or gas
  • FireRock offers firestops, stabilizers, storm collars and chimney caps that act as spark arrestors
  • Use 14" diameter pipe for all units with exception to 30" fireplace (12")
  • Our system allows for any UL 103 listed metal chimney

Important: Please consult local building codes for specifics regarding any masonry fireplace or chimney applications.

Masonry Fireplace Accessories - Metal Chimney System

Height Extension Kit

With the exception of Rumford, FireRock units come standard with a 34.5″ opening height. FireRock’s Height Extension Kit can be used to increase the firebox’s finished opening by almost nine inches. This accessory is perfect for designs that call for an arched opening that would normally reduce the open area of the firebox.

A Height Extension Kit is a three-piece unit that sets on the baseplace and raises the opening height by 8-5/8".

  • This accessory may not be used with LiteRock or See-Through models.
  • Treat as another layer of block at installation.

Important: Please consult local building codes for specifics regarding any masonry fireplace application.

Masonry Fireplace Height Extension Kit

Solid Block Chimney

FireRock’s patented one-piece interlocking components make it easy to add an all-masonry chimney to your fireplace. Approved for indoor and outdoor fireplaces, these nesting blocks may be stacked as high as building code allows. Use FireRock’s Bricking Flange in conjunction with the Solid Block Chimney to add a brick, stone, or stucco veneer above the roof. This Solid Block Chimney is required if our plans call for a Bricking Flange.

Independently tested at 3,000 PSI compressive strength, pieces may be stacked as high as local building codes allow for masonry chimneys. To increase the solid block chimney's strength even more, insert rebar and mortar into the "hurricane" holes.

  • Each piece is 6″ tall
  • Additional measurements: 22" (W) x 22" (L)
  • No flue liner necessary
  • 15″ diameter flue, largest round masonry flue in the industry, plus no flue liner necessary
  • UL 127 compliant for “zero clearance” to combustibles in verticle applications

Important: Please consult local building codes for specifics regarding any masonry fireplace application.

Masonry Fireplace Accessories - Solid Block Chimney

Outside Air Kit

  • FireRock recommends the Air-A-Lator Mason's Choice outside air intake regulatgor for all indoor fireplace installations
  • Helps stop backdraft smoking caused by negative pressure in home
  • Fire burns warmer, cleaner and safer because regulated outside air is used for combustion
  • Outside air kits should be installed and used in accordance with requirements of the standard for fireplaces under national code NFPA 211
  • FireRock recommends installing the outside air kit above the first course of firebrick near the front of the fireplace
  • Control both the volume of air and direction of air with these unique products

Important: Please consult local building codes for specifics regarding any masonry fireplace application.

Outside Air Kit

Installation Kits

For added convenience, FireRock offers installation kits for each indoor and outdoor product. Ask your local FireRock dealer to learn more about selecting the kit that's right for your project. Standard kit items include the following: 

  • # of Bags of FireRock Adhesive Mortar needed to complete your installation of firebox and firebrick
  • # of Firebricks needed for firebox in specified design and color
  • Cast iron throat damper in the correct size needed for firebox (indoor models only)
  • Angled steel bar needed to create lintel component (sizes 30"-48" only)
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Not sure what direction you want to take with your next project? Contact us to learn from our experts.

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