2103A Masonry Construction Materials — 2025 California Building Code
California Building Code (Title 24, Part 2) · 2025 edition · updated 2026-09-25 · California
CBSC: official editions, supplements and errata
Italicized text is a California amendment to the model code, as printed in the official publication.
Cite as: 2025 California Building Code (Title 24, Part 2) § 2103A · Effective January 1, 2026 · Official source: Building Standards Commission
2103 A .1 Masonry units. Concrete masonry units, clay or shale masonry units, stone masonry units, glass unit masonry shall comply with Article 2.3 of TMS 602. Architectural cast stone shall conform to TMS 504. Architectural cast stone construction shall be considered as an alternative system.
Exception: Structural clay tile for nonstructural use in fireproofing of structural members and in wall furring shall not be required to meet the compressive strength specifications. The fire-resistance rating shall be determined in accordance with ASTM E119 or UL 263 and shall comply with the requirements of Table 705.5.
2103 A .1.1 Second-hand units. Second-hand masonry units shall not be reused unless they conform to the requirements of new units. The units shall be of whole, sound materials and free from cracks and other defects that will interfere with proper laying or use. Old mortar shall be cleaned from the unit before reuse.
2103 A .2 Mortar. Mortar for masonry construction shall comply with Section 2103 A .2.1, 2103 A .2.2, 2103 A .2.3 or 2103 A .2.4.
2103 A .2.1 Masonry mortar. Mortar for use in masonry construction shall conform to Articles 2.1 and 2.6 A of TMS 602.
2103 A .2.2 Surface-bonding mortar. Surface-bonding mortar shall comply with ASTM C887. Surface bonding of concrete masonry units shall comply with ASTM C946.
2103 A .2.3 Mortars for ceramic wall and floor tile. Portland cement mortars for installing ceramic wall and floor tile shall comply with ANSI A108.1A and ANSI A108.1B and be of the compositions indicated in Table 2103 A .2.3.
TABLE 2103A.2.3—CERAMIC TILE MORTAR COMPOSITIONS
| LOCATION | MORTAR | COMPOSITION |
|---|---|---|
| Walls | Scratchcoat | 1 cement;1/5 hydrated lime; 4 dry or 5 damp sand |
| Walls | Setting bed and leveling coat | 1 cement;1/2 hydrated lime; 5 damp sand to 1 cement; 1 hydrated lime, 7 damp sand |
| Floors | Setting bed | 1 cement;1/10 hydrated lime; 5 dry or 6 damp sand; or 1 cement; 5 dry or 6 damp sand |
| Ceilings | Scratchcoat and sand bed | 1 cement;1/2 hydrated lime; 21/2 dry sand or 3 damp sand |
2103 A .2.3.1 Dry-set Portland cement mortars. Premixed prepared Portland cement mortars, which require only the addition of water and are used in the installation of ceramic tile, shall comply with ANSI A118.1. The shear bond strength for tile set in such mortar shall be as required in accordance with ANSI A118.1. Tile set in dry-set Portland cement mortar shall be installed in accordance with ANSI A108.5.
2103 A .2.3.2 Latex-modified Portland cement mortar. Latex-modified Portland cement thin-set mortars in which latex is added to dry-set mortar as a replacement for all or part of the gauging water that are used for the installation of ceramic tile shall comply with ANSI A118.4. Tile set in latex-modified Portland cement shall be installed in accordance with ANSI A108.5.
2103 A .2.3.3 Epoxy mortar. Ceramic tile set and grouted with chemical-resistant epoxy shall comply with ANSI A118.3. Tile set and grouted with epoxy shall be installed in accordance with ANSI A108.6.
2103 A .2.3.4 Furan mortar and grout. Chemical-resistant furan mortar and grout that are used to install ceramic tile shall comply with ANSI A118.5. Tile set and grouted with furan shall be installed in accordance with ANSI A108.8.
2103 A .2.3.5 Modified epoxy-emulsion mortar and grout. Modified epoxy-emulsion mortar and grout that are used to install ceramic tile shall comply with ANSI A118.8. Tile set and grouted with modified epoxy-emulsion mortar and grout shall be installed in accordance with ANSI A108.9.
2103 A .2.3.6 Organic adhesives. Water-resistant organic adhesives used for the installation of ceramic tile shall comply with ANSI A136.1. The shear bond strength after water immersion shall be not less than 40 psi (275 kPa) for Type I adhesive and not
21A-4 2025 CALIFORNIA BUILDING CODE
MASONRY
less than 20 psi (138 kPa) for Type II adhesive when tested in accordance with ANSI A136.1. Tile set in organic adhesives shall be installed in accordance with ANSI A108.4.
2103 A .2.3.7 Portland cement grouts. Portland cement grouts used for the installation of ceramic tile shall comply with ANSI A118.6. Portland cement grouts for tile work shall be installed in accordance with ANSI A108.10.
2103 A .2.4 Mortar for adhered masonry veneer. Mortar for use with adhered masonry veneer shall conform to Section 13.3 of TMS 402.
2103 A .3 Grout. Grout shall comply with Article 2.2 of TMS 602.
2103A.3.1 Aggregate. Coarse grout shall be used in grout spaces between wythes of 2 inches (50.8 mm) or more in width as deter- mined in accordance with TMS 602 Table 7, footnote 3, and in all grouted cells of hollow unit masonry construction.
2103 A .4 Metal reinforcement and accessories. Metal reinforcement and accessories shall conform to Article 2.4 of TMS 602. Where unidentified reinforcement, or bar reinforcement without mill certification, is approved for use, not less than three tension and three bending tests shall be made on representative specimens of the reinforcement from each shipment and grade of reinforcing steel proposed for use in the work. Alternatively, the frequency of sampling for unidentifiable reinforcing bars specified in Section 1910.2 can be used.
2103A.5 Air entrainment.¶
Air-entraining materials or air-entraining admixtures shall not be used in grout.
2103A.6 Specified compressive strength of masonry and grout¶
. Replace TMS 402 Table 4.3.1 by the following:
TABLE 4.3.1—SPECIFIED COMPRESSIVE STRENGTH REQUIREMENTS
| TYPE OF MASONRY | SPECIFIED COMPRESSIVE STRENGTH OF MASONRY | SPECIFIED COMPRESSIVE STRENGTH OF GROUT |
|---|---|---|
| Concrete masonry | 2,000 psi (13.79 MPa) ≤ f'm ≤ 3,000 psi (20.68 MPa) | f'g ≥ f'm ≤ 5,000 psi (34.47 MPa) |
| Clay masonry | 1,500 psi (10.34 MPa) ≤ f'm ≤ 4,500 psi (31.02 MPa) | f'g≤ 6,000 (41.37 MPa) |
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