CRC · California Residential Code

How must footings, foundations and ash cleanouts be constructed for masonry fireplaces?

Footings for a masonry fireplace must be concrete or solid masonry at least 12 inches thick, extend 6 inches beyond the fireplace on every side, and rest on undisturbed soil or engineered fill below the local frost depth (or be at least 12 inches below grade where freezing doesn’t occur). If you install an ash-dump cleanout in the foundation wall, it must use a metal or masonry door/frame that stays tightly closed except when used and be located so ash removal won’t endanger combustible materials (see § R1001.2 and § R1001.2.1) .

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Last reviewed: July 6, 2026

What the code requires — 2-4 sentences

Footings and foundations for masonry fireplaces must be built of concrete or solid masonry at least 12 inches thick and must project not less than 6 inches beyond the face of the fireplace or foundation wall on all sides (§ R1001.2) . Footings must be founded on natural, undisturbed earth or engineered fill below frost depth, or (in areas not subjected to freezing) placed not less than 12 inches below finished grade (§ R1001.2) . Where an ash dump cleanout is provided in the foundation wall below the firebox, it must have ferrous metal or masonry doors and frames that remain tightly closed except when in use and be located so ash removal does not create a hazard to combustibles (§ R1001.2.1) .

The single most important rule: footings must be a minimum 12 in thick, project 6 in beyond the fireplace face, and be founded below the local frost depth (or 12 in below grade where freezing does not occur) — and any ash cleanout in the foundation must be noncombustible and kept closed except when used (§ R1001.2; § R1001.2.1) .

Requirements in detail

Footings and foundation construction (controlling text)

  • Material: concrete or solid masonry. The code specifies concrete or solid masonry footings for fireplaces and chimneys (§ R1001.2) .
  • Minimum thickness: 12 inches (§ R1001.2) .
  • Projection: must extend not less than 6 inches beyond the face of the fireplace or foundation wall on all sides (§ R1001.2) .
  • Bearing/foundation depth:
    • Footings must be founded on natural, undisturbed earth or engineered fill below frost depth; where freezing is not a concern, footings must be not less than 12 inches below finished grade (§ R1001.2) .

Ash-dump / cleanout construction (controlling text)

  • Where provided, cleanout openings within foundation walls below fireboxes:
    • Must be equipped with ferrous metal or masonry doors and frames.
    • Doors/frames must be constructed to remain tightly closed except when in use.
    • Cleanouts must be located and accessible so that ash removal will not create a hazard to combustible materials (§ R1001.2.1) .

Decision-relevant dimensions & values

Item Required value / action Code reference
Footing thickness 12 in (305 mm) minimum § R1001.2
Footing projection beyond face 6 in (152 mm) minimum on all sides § R1001.2
Foundation bearing condition Founded on natural, undisturbed earth or engineered fill below frost depth § R1001.2
Footing depth (no freezing) 12 in (305 mm) below finished grade minimum § R1001.2
Ash dump cleanout door/frame material Ferrous metal or masonry § R1001.2.1
Cleanout closure Must remain tightly closed except when in use § R1001.2.1
Cleanout location Accessible; positioned so ash removal does not endanger combustibles § R1001.2.1

Exceptions & special cases

  • Frost-depth exception: In regions not subjected to freezing, the code does not require the footing to be founded below frost depth; instead it requires the footing to be not less than 12 inches below finished grade (§ R1001.2) .
  • Cleanouts are required “where provided” — the code prescribes construction and closure requirements only for cleanouts that are actually installed; it does not mandate that every fireplace must have an ash dump cleanout (§ R1001.2.1) .
  • The sections cited do not specify exact clearances or door sizes for cleanouts — only material and that the location must not create a hazard to combustible materials (see Limitations below).

Note: The code text in § R1001.2 and § R1001.2.1 controls these items; other aspects of foundation sizing (bearing area, allowable soil pressure, continuous footings in certain seismic zones) are addressed elsewhere in the CRC (see Related provisions below) and must be used where applicable.

Common mistakes

  • Installing a footing thinner than 12 in or failing to extend it 6 in beyond the fireplace face. The code minimums are explicit in § R1001.2 .
  • Placing the footing shallow in a freeze zone — footings must be founded below local frost depth; treating freeze and non-freeze regions the same leads to frost heave and damage (§ R1001.2) .
  • Using combustible materials for cleanout doors or frames. Cleanout openings must be provided with ferrous metal or masonry doors/frames (§ R1001.2.1) .
  • Locating a cleanout where ash removal will drip or fall onto combustible framing or finishes. § R1001.2.1 requires cleanouts be located so ash removal will not create a hazard to combustible materials .
  • Assuming the code prescribes door size, clearance dimensions around the cleanout, or specific hardware — § R1001.2.1 does not give those sizes; those are left to good practice, manufacturer instructions, or local authority interpretation .

Worked example — concrete scenario with numbers

Scenario: You are building a masonry fireplace whose finished foundation wall (face-to-face) is 40 inches wide. The project is in a location where the local frost depth is 30 inches.

Steps and code application:

  1. Footing thickness: Use 12 in thick footing (minimum) per § R1001.2 .
  2. Footing projection: Extend the footing 6 in beyond the face on all sides. For a 40 in face width:
    • Total footing width = fireplace width + 2 × projection = 40 in + 2 × 6 in = 52 in.
    • (If the fireplace has narrower walls on one side, apply the 6 in extension around the entire footprint — code requires projection “on all sides” § R1001.2.)
  3. Foundation depth (freeze area): Footing bottom must be below the frost depth. If frost depth = 30 in, place the footing so its bottom is at least 30 in below finished grade (practically, excavate to slightly deeper to achieve required minimum bearing and allow for footing thickness) (§ R1001.2) .
  4. Ash cleanout (if provided): If you install an ash dump cleanout in the foundation wall below the firebox, provide a ferrous metal or masonry door and frame that remains tightly closed except when in use, and locate it so ash removal will not create a hazard to nearby combustible materials (§ R1001.2.1) .

Result: For this example you would pour a 12 in thick concrete footing spanning 52 in for the 40 in fireplace, with the bottom of the footing placed below 30 in from finished grade, and an ash cleanout (if provided) built with a metal or masonry door that seals when closed.

Related provisions

  • § R1001.1 — General requirements for masonry fireplaces (context for § R1001.2) .
  • § R1001.3 — Seismic reinforcing requirements for masonry fireplaces and chimneys (when reinforcement is required) .
  • § R1003.2 — Footings and foundations for masonry chimneys (similar footing rules for chimneys) .
  • § R606.3.5.2 — Cleanouts required for grouted masonry pours (related to grout cleanouts in masonry; not specifically for ash cleanouts) .
  • Table R1001.1 — Summary table of fireplace requirements, including footing items (use for quick reference; see the table notes in the code) .

If you need, I can extract the exact code text for any of the related sections above or produce a site-specific checklist for your project (freeze zone, soil-bearing, seismic category, cleanout detail, and typical door model recommendations).

Code references

Grounded in the retrieved California Residential Code — click a citation to read the verbatim passage:

  • CRC § 2.1 High relevance — show source text

    R1001.2 Footings and foundations. Footings for masonry fireplaces and their chimneys shall be constructed of concrete or solid masonry not less than 12 inches (305 mm) thick and shall extend not less than 6 inches (152 mm) beyond the face of the fireplace or foundation wall on all sides. Footings shall be founded on natural, undisturbed earth or engineered fill below frost depth. In areas not subjected to freezing, footings shall be not less than 12 inches (305 mm) below finished grade.

    R1001.2.1 Ash dump cleanout. Cleanout openings located within foundation walls below fireboxes, where provided, shall be equipped with ferrous metal or masonry doors and frames constructed to remain tightly closed except when in use. Cleanouts shall be located to allow access so that ash removal will not create a hazard to combustible materials.

    R1001.3 Seismic reinforcing. Masonry or concrete chimneys in all structures regulated by this code assigned to Seismic Design Category C, D 0, D 1 or D 2 shall be reinforced. Reinforcing shall conform to the requirements set forth in Table R1001.1 and Section R606.

    R1001.3.1 Vertical reinforcing. For chimneys up to 40 inches (1016 mm) wide, four No. 4 continuous vertical bars shall be placed between wythes of solid masonry or within the cells of hollow unit masonry and grouted in accordance with Section R606. Grout

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    shall be prevented from bonding with the flue liner so that the flue liner is free to move with thermal expansion. For chimneys more than 40 inches (1016 mm) wide, two additional No. 4 vertical bars shall be provided for each additional flue incorporated into the chimney or for each additional 40 inches (1016 mm) in width or fraction thereof. R1001.3.2 Horizontal reinforcing. Vertical reinforcement shall be placed within [1] / 4 -inch (6.4 mm) ties, or other reinforcing of equivalent net cross-sectional area, placed in the bed joints in accordance with Section R606 at not less than every 18 inches (457 mm) of vertical height. Two such ties shall be installed at each bend in the vertical bars.

    R1001.4 Seismic anchorage. Masonry or concrete chimneys in all structures regulated by this code assigned to Seismic Design Category C, D 0, D 1 or D 2 shall be anchored at each floor, ceiling or roof line more than 6 feet (1829 mm) above grade, except where constructed completely within the exterior walls. Anchorage shall conform to the requirements of Section R1001.4.1. R1001.4.1 Anchorage. Two [3] / 16 -inch by 1-inch (5 mm by 25 mm) straps shall be embedded not less than 12 inches (305 mm) into the chimney. Straps shall be hooked around the outer bars and extend 6 inches (152 mm) beyond the bend. Each strap shall be fastened to not less than four floor ceiling or floor joists or rafters with two [1] / 2 -inch (12.7 mm) bolts. **R1001.4.1.1 Cold-formed steel framing.

  • CRC § 404.6 High relevance — show source text

    Exceptions:

    1. Glass-block assemblies having a fire protection rating of not less than [3] / 4 hour shall be permitted as opening protectives in accordance with Section 716 in fire barriers, fire partitions and smoke barriers that have a required fireresistance rating of 1 hour or less and do not enclose exit stairways and ramps or exit passageways.
    2. Glass-block assemblies as permitted in Section 404.6, Exception 2.

    SECTION 2111—MASONRY FIREPLACES

    2111.1 General. The construction of masonry fireplaces, consisting of concrete or masonry, shall be in accordance with this section.

    2111.2 Fireplace drawings. The construction documents shall describe in sufficient detail the location, size and construction of masonry fireplaces. The thickness and characteristics of materials and the clearances from walls, partitions and ceilings shall be indicated.

    2111.3 Footings and foundations. Footings for masonry fireplaces and their chimneys shall be constructed of concrete or solid masonry not less than 12 inches (305 mm) thick and shall extend not less than 6 inches (153 mm) beyond the face of the fireplace or foundation wall on all sides. Footings shall be founded on natural undisturbed earth or engineered fill below frost depth. In areas not subjected to freezing, footings shall be not less than 12 inches (305 mm) below finished grade.

    2111.3.1 Ash dump cleanout. Cleanout openings, located within foundation walls below fireboxes, where provided, shall be equipped with ferrous metal or masonry doors and frames constructed to remain tightly closed, except when in use. Cleanouts shall be accessible and located so that ash removal will not create a hazard to combustible materials.

    2111.4 Seismic reinforcement. In structures assigned to Seismic Design Category A or B, seismic reinforcement is not required. In structures assigned to Seismic Design Category C or D, masonry fireplaces shall be reinforced and anchored in accordance with Sections 2111.4.1, 2111.4.2 and 2111.5. In structures assigned to Seismic Design Category E or F, masonry fireplaces shall be reinforced in accordance with the requirements of Sections 2101 through 2108.

    2111.4.1 Vertical reinforcing. For fireplaces with chimneys up to 40 inches (1016 mm) wide, four No. 4 continuous vertical bars, anchored in the foundation, shall be placed in the concrete between wythes of solid masonry or within the cells of hollow unit masonry and grouted in accordance with Section 2103.3. For fireplaces with chimneys greater than 40 inches (1016 mm) wide, two additional No. 4 vertical bars shall be provided for each additional 40 inches (1016 mm) in width or fraction thereof. 2111.4.2 Horizontal reinforcing. Vertical reinforcement shall be placed enclosed within [1] / 4 -inch (6.4 mm) ties or other reinforcing of equivalent net cross-sectional area, spaced not to exceed 18 inches (457 mm) on center in concrete; or placed in the bed joints of unit masonry at not less than every 18 inches (457 mm) of vertical height. Two such ties shall be provided at each bend in the vertical bars.

  • CRC § 25.4 High relevance — show source text

    Not required in Seismic Design Category A or B.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 square foot = 0.0929 m2.
    Note: This table provides a summary of major requirements for the construction of masonry chimneys and fireplaces. Letter references are to Figure R1001.1, which shows
    examples of typical construction. This table does not cover all requirements, nor does it cover all aspects of the indicated requirements. For the actual mandatory require-
    ments of the code, see the indicated section of text.
    a. The letters refer to Figure R1001.1.
    b. Not required in Seismic Design Category A or B.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 square foot = 0.0929 m2.
    Note: This table provides a summary of major requirements for the construction of masonry chimneys and fireplaces. Letter references are to Figure R1001.1, which shows
    examples of typical construction. This table does not cover all requirements, nor does it cover all aspects of the indicated requirements. For the actual mandatory require-
    ments of the code, see the indicated section of text.
    a. The letters refer to Figure R1001.1.
    b. Not required in Seismic Design Category A or B.|

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    For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.

    FIGURE R1001.1—FIREPLACE AND CHIMNEY DETAILS

    R1001.2 Footings and foundations. Footings for masonry fireplaces and their chimneys shall be constructed of concrete or solid masonry not less than 12 inches (305 mm) thick and shall extend not less than 6 inches (152 mm) beyond the face of the fireplace or foundation wall on all sides. Footings shall be founded on natural, undisturbed earth or engineered fill below frost depth. In areas not subjected to freezing, footings shall be not less than 12 inches (305 mm) below finished grade.

    R1001.2.1 Ash dump cleanout. Cleanout openings located within foundation walls below fireboxes, where provided, shall be equipped with ferrous metal or masonry doors and frames constructed to remain tightly closed except when in use. Cleanouts shall be located to allow access so that ash removal will not create a hazard to combustible materials.

    R1001.3 Seismic reinforcing. Masonry or concrete chimneys in all structures regulated by this code assigned to Seismic Design Category C, D 0, D 1 or D 2 shall be reinforced. Reinforcing shall conform to the requirements set forth in Table R1001.1 and Section R606.

    R1001.3.1 Vertical reinforcing. For chimneys up to 40 inches (1016 mm) wide, four No. 4 continuous vertical bars shall be placed between wythes of solid masonry or within the cells of hollow unit masonry and grouted in accordance with Section R606. Grout

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  • CRC § 4.1 High relevance — show source text

    Footing thickness and projection for fireplaces shall be in accordance with Section R1001.2. The size of footings supporting piers and columns shall be based on the tributary load and allowable soil pressure in accordance with Table R401.4.1(1). Footings for wood foundations shall be in accordance with the details set forth in Section R403.2, and Figures R403.1(2) and R403.1(3). Footings for precast foundations shall be in accordance with the details set forth in Section R403.4, Table R403.4, and Figures R403.4(1) and R403.4(2). Crushed stone footings for cast-in-place concrete foundations shall be in accordance with Section R403.5.

    R403.1.2 Continuous footing in Seismic Design Categories D 0 , D 1 and D 2 . Exterior walls and required interior braced wall panels of buildings located in Seismic Design Categories D 0, D 1 and D 2 shall be supported by continuous solid or fully grouted masonry or concrete footings in accordance with Table R403.1.2. Other footing materials or systems shall be designed in accordance with accepted engineering practice.

    TABLE R403.1.2—CONTINUOUS FOOTING REQUIREMENTS IN SEISMIC DESIGN CATEGORIES D, D AND D
    0 1 2    		 Col2 Col3 Col4 Col5 Col6 Col7 Col8 Col9 Col10 Col11 Col12 Col13 Col14 Col15
    BUILDING PLAN DIMENSIONS 1-STORY 1-STORY 1-STORY 1-STORY 1-STORY 1-STORY 2-STORY 2-STORY 2-STORY 2-STORY 2-STORY 2-STORY 3-STORY 3-STORY
    BUILDING PLAN DIMENSIONS 50 feet or less 50 feet or less 50 feet or less > 50 feet > 50 feet > 50 feet 50 feet or less 50 feet or less 50 feet or less > 50 feet > 50 feet > 50 feet Any Any
    SDC D_0_ D_1_ D_2_ D_0_ D_1_ D_2_ D_0_ D_1_ D_2_ D_0_ D_1_ D_2_ D_0_ D_1_
    Continuous footings supporting exterior walls R R R R R R R R R R R R R R
    Continuous footings supporting required inte-
    rior braced wall panels    		 NR NR NR Ra Ra Ra NR NR Ra Ra Ra Ra R R
    For SI: 1 foot = 304.8 mm.
    R = Continuous solid or fully grouted masonry or concrete footings in accordance with Section R403.1.3.4 required.
    NR = Continuous footings not required.
    a.
  • CRC § 8-7 High relevance — show source text

    R1002.5 Masonry heater clearance. Combustible materials shall not be placed within 36 inches (914 mm) of the outside surface of a masonry heater in accordance with NFPA 211 Section 8-7 (clearances for solid-fuel-burning appliances), and the required space between the heater and combustible material shall be fully vented to permit the free flow of air around all heater surfaces.

    Exceptions:

    1. Where the masonry heater wall is not less than 8 inches (203 mm) thick of solid masonry and the wall of the heat exchange channels is not less than 5 inches (127 mm) thick of solid masonry, combustible materials shall not be placed within 4 inches (102 mm) of the outside surface of a masonry heater. A clearance of not less than 8 inches (203 mm) shall be provided between the gas-tight capping slab of the heater and a combustible ceiling.
    2. Masonry heaters listed and labeled in accordance with UL 1482 or CEN 15250 shall be installed in accordance with the listing specifications and the manufacturer’s written instructions.

    SECTION R1003—MASONRY CHIMNEYS

    R1003.1 Definition. A masonry chimney is a chimney constructed of solid masonry units, hollow masonry units grouted solid, stone or concrete, hereinafter referred to as masonry. Masonry chimneys shall be constructed, anchored, supported and reinforced as required in this chapter.

    R1003.2 Footings and foundations. Footings for masonry chimneys shall be constructed of concrete or solid masonry not less than 12 inches (305 mm) thick and shall extend not less than 6 inches (152 mm) beyond the face of the foundation or support wall on all sides. Footings shall be founded on natural undisturbed earth or engineered fill below frost depth. In areas not subjected to freezing, footings shall be not less than 12 inches (305 mm) below finished grade.

    R1003.3 Seismic reinforcing. Masonry or concrete chimneys shall be constructed, anchored, supported and reinforced as required in this chapter. In all structures regulated by this code assigned to Seismic Design Category C, D 0, D 1 or D 2 masonry and concrete chimneys shall be reinforced and anchored as detailed in Sections R1003.3.1, R1003.3.2 and R1003.4. In Seismic Design Category A or B, reinforcement and seismic anchorage are not required.

    R1003.3.1 Vertical reinforcing. For chimneys up to 40 inches (1016 mm) wide, four No. 4 continuous vertical bars, anchored in the foundation, shall be placed in the concrete, or between wythes of solid masonry, or within the cells of hollow unit masonry, and grouted in accordance with Section R608.1.1. Grout shall be prevented from bonding with the flue liner so that the flue liner is free to move with thermal expansion. For chimneys more than 40 inches (1016 mm) wide, two additional No. 4 vertical bars shall be installed for each additional 40 inches (1016 mm) in width or fraction thereof.

  • CRC § 2.3 High relevance — show source text

    FINISH GRADE SLOPE [1] / 2 IN. PER FOOT, MIN. 6 FT. FROM WALL

    16 IN.

    PRESSURE-PRESERVATIVE TREATED 2 � 6 IN. STUD WALL

    PRESSURE-PRESERVATIVE TREATED PLYWOOD (SEE TABLE R404.2.3)

    PRESSURE-PRESERVATIVE TREATED 2 � 6 IN. BOTTOM PLATE

    PRESSURE-PRESERVATIVE TREATED 2 � 8 IN. FOOTING PLATE

    BELOW FROST LINE

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    FOUNDATIONS

    R403.1.1 Minimum size. The minimum width, W, and thickness, T, for concrete footings shall be in accordance with Tables R403.1(1) through R403.1(3) and Figure R403.1(1) or R403.1.3, as applicable, but not less than 12 inches (305 mm) in width and 6 inches (152 mm) in depth. The footing width shall be based on the load-bearing value of the soil in accordance with Table R401.4.1(1). Footing projections, P, shall be not less than 2 inches (51 mm) and shall not exceed the thickness of the footing. Footing thickness and projection for fireplaces shall be in accordance with Section R1001.2. The size of footings supporting piers and columns shall be based on the tributary load and allowable soil pressure in accordance with Table R401.4.1(1). Footings for wood foundations shall be in accordance with the details set forth in Section R403.2, and Figures R403.1(2) and R403.1(3). Footings for precast foundations shall be in accordance with the details set forth in Section R403.4, Table R403.4, and Figures R403.4(1) and R403.4(2). Crushed stone footings for cast-in-place concrete foundations shall be in accordance with Section R403.5.

    R403.1.2 Continuous footing in Seismic Design Categories D 0 , D 1 and D 2 . Exterior walls and required interior braced wall panels of buildings located in Seismic Design Categories D 0, D 1 and D 2 shall be supported by continuous solid or fully grouted masonry or concrete footings in accordance with Table R403.1.2. Other footing materials or systems shall be designed in accordance with accepted engineering practice.

    TABLE R403.1.2—CONTINUOUS FOOTING REQUIREMENTS IN SEISMIC DESIGN CATEGORIES D, D AND D
    0 1 2    		 Col2 Col3 Col4 Col5 Col6 Col7 Col8 Col9 Col10 Col11 Col12 Col13 Col14 Col15
    **BUILDING PLAN
  • CRC § 2109.2.4.8.9.3 High relevance — show source text

    2109.2.4.8.9.3 Weather-exposed locations. Clay plaster exposed to water from direct or wind-driven rain or snow shall be finished with an approved erosion-resistant finish. The use of clay plasters shall not be permitted on weather-exposed parapets.

    2109.2.4.8.9.4 Prohibited finish coat. Plaster containing Portland cement shall not be permitted as a finish over clay plaster.

    2109.2.4.8.9.5 Conditions where lathing is not required. For unstabilized adobe walls finished with unstabilized clay plaster, lathing shall not be required.

    2109.2.4.9 Lintels. Lintels shall be considered to be structural members and shall be designed in accordance with the applicable provisions of Chapter 16.

    SECTION 2110—GLASS UNIT MASONRY

    2110.1 General. [OSHPD 1R, 2 & 5] Masonry glass block walls or panels shall be designed for seismic forces. Stresses in glass block shall not be utilized. Glass unit masonry construction shall comply with Chapter 14 of TMS 402 and this section.

    2110.1.1 Limitations. Solid or hollow approved glass block shall not be used in fire walls, party walls, fire barriers, fire partitions or smoke barriers, or for load-bearing construction. Such blocks shall be erected with mortar and reinforcement in metal channeltype frames, structural frames, masonry or concrete recesses, embedded panel anchors as provided for both exterior and interior walls or other approved joint materials. Wood strip framing shall not be used in walls required to have a fire-resistance rating by other provisions of this code.

    Exceptions:

    1. Glass-block assemblies having a fire protection rating of not less than [3] / 4 hour shall be permitted as opening protectives in accordance with Section 716 in fire barriers, fire partitions and smoke barriers that have a required fireresistance rating of 1 hour or less and do not enclose exit stairways and ramps or exit passageways.
    2. Glass-block assemblies as permitted in Section 404.6, Exception 2.

    SECTION 2111—MASONRY FIREPLACES

    2111.1 General. The construction of masonry fireplaces, consisting of concrete or masonry, shall be in accordance with this section.

    2111.2 Fireplace drawings. The construction documents shall describe in sufficient detail the location, size and construction of masonry fireplaces. The thickness and characteristics of materials and the clearances from walls, partitions and ceilings shall be indicated.

    2111.3 Footings and foundations. Footings for masonry fireplaces and their chimneys shall be constructed of concrete or solid masonry not less than 12 inches (305 mm) thick and shall extend not less than 6 inches (153 mm) beyond the face of the fireplace or foundation wall on all sides. Footings shall be founded on natural undisturbed earth or engineered fill below frost depth. In areas not subjected to freezing, footings shall be not less than 12 inches (305 mm) below finished grade.

    2111.3.1 Ash dump cleanout. Cleanout openings, located within foundation walls below fireboxes, where provided, shall be equipped with ferrous metal or masonry doors and frames constructed to remain tightly closed, except when in use. Cleanouts shall be accessible and located so that ash removal will not create a hazard to combustible materials.

  • CRC § 3.1 High relevance — show source text

    2111 A .3.1 Ash dump cleanout. Cleanout openings, located within foundation walls below fireboxes, where provided, shall be equipped with ferrous metal or masonry doors and frames constructed to remain tightly closed, except when in use. Cleanouts shall be accessible and located so that ash removal will not create a hazard to combustible materials.

    2111 A .4 Seismic reinforcement. In structures assigned to Seismic Design Category A or B, seismic reinforcement is not required. In structures assigned to Seismic Design Category C or D, masonry fireplaces shall be reinforced and anchored in accordance with Sections 2111 A .4.1, 2111 A .4.2 and 2111 A .5. In structures assigned to Seismic Design Category E or F, masonry fireplaces shall be reinforced in accordance with the requirements of Sections 2101 A through 2108 A .

    2111 A .4.1 Vertical reinforcing. For fireplaces with chimneys up to 40 inches (1016 mm) wide, four No. 4 continuous vertical bars, anchored in the foundation, shall be placed in the concrete between wythes of solid masonry or within the cells of hollow unit masonry and grouted in accordance with Section 2103.3. For fireplaces with chimneys greater than 40 inches (1016 mm) wide, two additional No. 4 vertical bars shall be provided for each additional 40 inches (1016 mm) in width or fraction thereof. 2111 A .4.2 Horizontal reinforcing. Vertical reinforcement shall be placed enclosed within [1] / 4 -inch (6.4 mm) ties or other reinforcing of equivalent net cross-sectional area, spaced not to exceed 18 inches (457 mm) on center in concrete; or placed in the bed joints of unit masonry at not less than every 18 inches (457 mm) of vertical height. Two such ties shall be provided at each bend in the vertical bars.

    2111 A .5 Seismic anchorage. Masonry fireplaces and foundations shall be anchored at each floor, ceiling or roof line more than 6 feet (1829 mm) above grade with two [3] / 16 -inch by 1-inch (4.8 mm by 25 mm) straps embedded not less than 12 inches (305 mm) into the chimney. Straps shall be hooked around the outer bars and extend 6 inches (152 mm) beyond the bend. Each strap shall be fastened to not fewer than four floor joists with two [1] / 2 -inch (12.7 mm) bolts.

    Exception: Seismic anchorage is not required for the following:

    1. In structures assigned to Seismic Design Category A or B.
    2. Where the masonry fireplace is constructed completely within the exterior walls.
  • CRC § 10-6 High relevance — show source text

    internal heat exchange channels in which the flow path downstream of the firebox includes flow in a horizontal or downward direction before entering the chimney and that delivers heat by radiation from the masonry surface of the heater.

    R1002.2 Installation. Masonry heaters shall be installed in accordance with this section and comply with one of the following:

    1. Masonry heaters shall comply with the requirements of ASTM E1602.
    2. Masonry heaters shall be listed and labeled in accordance with UL 1482 or CEN 15250 and installed in accordance with the manufacturer’s instructions.

    R1002.3 Footings and foundation. The firebox floor of a masonry heater shall be a minimum thickness of 4 inches (102 mm) of noncombustible material and be supported on a noncombustible footing and foundation in accordance with Section R1003.2.

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    R1002.4 Seismic reinforcing. In Seismic Design Categories D 0, D 1 and D 2, masonry heaters shall be anchored to the masonry foundation in accordance with Section R1003.3. Seismic reinforcing shall not be required within the body of a masonry heater whose height is equal to or less than 3.5 times its body width and where the masonry chimney serving the heater is not supported by the body of the heater. Where the masonry chimney shares a common wall with the facing of the masonry heater, the chimney portion of the structure shall be reinforced in accordance with Section R1003.

    R1002.5 Masonry heater clearance. Combustible materials shall not be placed within 36 inches (914 mm) of the outside surface of a masonry heater in accordance with NFPA 211 Section 8-7 (clearances for solid-fuel-burning appliances), and the required space between the heater and combustible material shall be fully vented to permit the free flow of air around all heater surfaces.

    Exceptions:

    1. Where the masonry heater wall is not less than 8 inches (203 mm) thick of solid masonry and the wall of the heat exchange channels is not less than 5 inches (127 mm) thick of solid masonry, combustible materials shall not be placed within 4 inches (102 mm) of the outside surface of a masonry heater. A clearance of not less than 8 inches (203 mm) shall be provided between the gas-tight capping slab of the heater and a combustible ceiling.
    2. Masonry heaters listed and labeled in accordance with UL 1482 or CEN 15250 shall be installed in accordance with the listing specifications and the manufacturer’s written instructions.

    SECTION R1003—MASONRY CHIMNEYS

    R1003.1 Definition. A masonry chimney is a chimney constructed of solid masonry units, hollow masonry units grouted solid, stone or concrete, hereinafter referred to as masonry. Masonry chimneys shall be constructed, anchored, supported and reinforced as required in this chapter.

  • CRC § 25.4 High relevance — show source text

    For grouting between masonry wythes.
    b. Grout space dimension is the clear dimension between any masonry protrusion and shall be increased by the horizontal projection of the diameters of the horizontal bars
    within the cross section of the grout space.
    c. Area of vertical reinforcement shall not exceed 6 percent of the area of the grout space.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
    a. For grouting between masonry wythes.
    b. Grout space dimension is the clear dimension between any masonry protrusion and shall be increased by the horizontal projection of the diameters of the horizontal bars
    within the cross section of the grout space.
    c. Area of vertical reinforcement shall not exceed 6 percent of the area of the grout space.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
    a. For grouting between masonry wythes.
    b. Grout space dimension is the clear dimension between any masonry protrusion and shall be increased by the horizontal projection of the diameters of the horizontal bars
    within the cross section of the grout space.
    c. Area of vertical reinforcement shall not exceed 6 percent of the area of the grout space.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
    a. For grouting between masonry wythes.
    b. Grout space dimension is the clear dimension between any masonry protrusion and shall be increased by the horizontal projection of the diameters of the horizontal bars
    within the cross section of the grout space.
    c. Area of vertical reinforcement shall not exceed 6 percent of the area of the grout space.|

    R606.3.5.2 Cleanouts. Provisions shall be made for cleaning the space to be grouted. Mortar that projects more than [1] / 2 inch (12.7 mm) into the grout space and any other foreign matter shall be removed from the grout space prior to inspection and grouting. Where required by the building official, cleanouts shall be provided in the bottom course of masonry for each grout pour where the grout pour height exceeds 64 inches (1626 mm). In solid grouted masonry, cleanouts shall be spaced horizontally not more than 32 inches (813 mm) on center. The cleanouts shall be sealed before grouting and after inspection.

    R606.3.5.3 Construction. Requirements for grouted masonry construction shall be as follows:

    1. Masonry shall be built to preserve the unobstructed vertical continuity of the cells or spaces to be filled. In partially grouted construction, cross webs forming cells to be filled shall be full-bedded in mortar to prevent leakage of grout. Head and end joints shall be solidly filled with mortar for a distance in from the face of the wall or unit not less than the thickness of the longitudinal face shells.
    2. Vertical reinforcement shall be held in position at top and bottom and at intervals not exceeding 200 diameters of the reinforcement.
  • CRC § 6.1.7.3.1 High relevance — show source text

    6.1.7.3.1 – Welded splices shall not be permitted in plastic hinge zones of intermediate or special reinforced walls.

    6.1.7.2.1 – Mechanical splices shall be classified as Type 1 or 2 in accordance with Section 18.2.7.1 of ACI 318. Type 1 mechanical splices shall not be used within a plastic hinge zone or within a beam-column joint of intermediate or special reinforced masonry shear walls. Type 2 mechanical splices are permitted in any location within a member.

    SECTION 2109 A —EMPIRICAL DESIGN OF ADOBE MASONRY

    Not permitted by OSHPD and DSA.

    SECTION 2110 A —GLASS UNIT MASONRY

    2110 A .1 General. Glass unit masonry construction shall comply with Chapter 14 of TMS 402 and this section.

    Masonry glass block walls or panels shall be designed for seismic forces. Stresses in glass block shall not be utilized.

    2110 A .1.1 Limitations. Solid or hollow approved glass block shall not be used in fire walls, party walls, fire barriers, fire partitions or smoke barriers, or for load-bearing construction. Such blocks shall be erected with mortar and reinforcement in metal channeltype frames, structural frames, masonry or concrete recesses, embedded panel anchors as provided for both exterior and interior walls or other approved joint materials. Wood strip framing shall not be used in walls required to have a fire-resistance rating by other provisions of this code.

    Exceptions:

    1. Glass-block assemblies having a fire protection rating of not less than [3] / 4 hour shall be permitted as opening protectives in accordance with Section 716 in fire barriers, fire partitions and smoke barriers that have a required fireresistance rating of 1 hour or less and do not enclose exit stairways and ramps or exit passageways.
    2. Glass-block assemblies as permitted in Section 404.6, Exception 2.

    SECTION 2111 A —MASONRY FIREPLACES

    2111 A .1 General. The construction of masonry fireplaces, consisting of concrete or masonry, shall be in accordance with this section.

    2111 A .2 Fireplace drawings. The construction documents shall describe in sufficient detail the location, size and construction of masonry fireplaces. The thickness and characteristics of materials and the clearances from walls, partitions and ceilings shall be indicated.

    2111 A .3 Footings and foundations. Footings for masonry fireplaces and their chimneys shall be constructed of concrete or solid masonry not less than 12 inches (305 mm) thick and shall extend not less than 6 inches (153 mm) beyond the face of the fireplace or

    21A-10 2025 CALIFORNIA BUILDING CODE

    on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

    MASONRY

    foundation wall on all sides. Footings shall be founded on natural undisturbed earth or engineered fill below frost depth. In areas not subjected to freezing, footings shall be not less than 12 inches (305 mm) below finished grade.

Frequently asked questions

Can I use a wood or plastic cleanout door in the foundation?

No. The code requires ferrous metal or masonry doors and frames for ash dump cleanouts located within foundation walls below the firebox (§ R1001.2.1) .

How far must the footing extend beyond the fireplace face?

The footing must extend not less than 6 inches beyond the face of the fireplace or foundation wall on all sides (§ R1001.2) .

How deep must the footing be in a non-freezing area?

In areas not subjected to freezing, footings shall be placed not less than 12 inches below finished grade (§ R1001.2) .

Does the code require an ash cleanout for every masonry fireplace?

No. § R1001.2.1 governs the construction of cleanouts where provided; it does not mandate that every fireplace include an ash dump cleanout (§ R1001.2.1) .

Are specific cleanout door sizes or clearances given?

No. § R1001.2.1 specifies materials and that the cleanout be accessible and not create a hazard to combustibles, but it does not specify door sizes or exact clearance distances — follow good practice and local authority guidance (§ R1001.2.1) .

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Masonry Fireplaces

California Residential Code