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Chapter 16 — REFERENCED STANDARDS

Section C103

California Existing Building Code (Title 24, Part 10) · 2022 edition · updated 2026-09-10 · California

Italicized text is a California amendment to the model code, as printed in the official publication.

MATERIALS OF CONSTRUCTION

[BS] C103.1 Existing materials. Existing wood materials that will be part of the retrofitting work (such as trusses, rafters, ceiling joists, top plates and wall studs) shall be in sound condition and free from defects or damage that substantially reduces the load-carrying capacity of the member. Any wood materials found to be damaged or deteriorated shall be strengthened or replaced with new materials to provide a net dimension of sound wood equivalent to its undamaged original dimensions.

[BS] C103.2 New materials. All new materials shall comply with the standards for those materials as specified in the California Building Code or the California Residential Code .

[BS] C103.3 Material specifications for retrofits. Materials for retrofitting gable end walls shall comply with Table C103.3.

[BS] C103.4 Twists in straps. Straps shall be permitted to be twisted or bent where they transition between framing

members or connection points. Straps shall be bent only once at a given location though it is permissible that they be bent or twisted at multiple locations along their length.

[BS] C103.5 Fasteners. Fasteners shall meet the requirements of Table C103.5, Sections C103.5.1 and C103.5.2, and shall be permitted to be screws or nails meeting the minimum length requirement shown in the figures and specified in the tables of this appendix. Fastener spacing shall meet the requirements of Section C103.5.3.

[BS] C103.5.1 Screws. Unless otherwise indicated in the appendix, screw sizes and lengths shall be in accordance with Table C103.5. Permissible screws include deck screws and wood screws. Screws shall have not less than 1 inch (25 mm) of thread. Fine threaded screws or drywall screws shall not be permitted. Select the largest possible diameter screw such that the shank adjacent to the head fits through the hole in the strap.

[BS] C103.5.2 Nails. Unless otherwise indicated in this appendix, nail sizes and lengths shall be in accordance with Table C103.5.

[BS] C103.5.3 General fastener spacing. Fastener spacing for shear connections of lumber-to-lumber shall meet the requirements shown in Figure C103.5.3 and the following conditions.

[BS] TABLE C103.3 MATERIAL SPECIFICATIONS FOR RETROFITS a

COMPONENT MINIMUM SIZE OR THICKNESS MINIMUM MATERIAL GRADE MINIMUM CAPACITY
Anchor blocks, compression
blocks and horizontal braces		 2 × 4 nominal lumber #2 Spruce-Pine-Fir or better NA
Nail plates 20 gage thickness 8d minimum
nail holes		 Galvanized sheet steel NA
Retrofit studs 2 × 4 nominal lumber #2 Spruce-Pine-Fir or better NA
Gusset angle 14 gage thickness Galvanized sheet steel 350 pounds uplift and lateral load
Stud-to-plate connector 20 gage thickness Galvanized sheet steel 500 pounds uplift
Metal plate connectors, straps and
anchors		 20 gage thickness Galvanized sheet steel NA

For SI: 1 pound = 4.4 N. NA = Not Applicable. a. Metal plate connectors, nail plates, stud-to-plate connectors, straps and anchors shall be products approved for connecting wood-to-wood or wood-to-concrete

as appropriate.

[BS] TABLE C103.5 NAIL AND SCREW REQUIREMENTS

FASTENER TYPE MINIMUM SHANK DIAMETER MINIMUM HEAD DIAMETER MINIMUM FASTENER LENGTH
#8 screws NA 0.28 inches 11/4 inches
8d common nails 0.131 inches 0.28 inches 21/2 inches
10d common nails 0.148 inches 0.28 inches 3 inches

For SI: 1 inch = 25.4 mm. NA = Not Applicable.

APPENDIX C-4 2022 CALIFORNIA EXISTING BUILDING CODE

Copyright © 2022 by, or licensed to, International Code Council, Inc. (ALL RIGHTS RESERVED); licensed to California Building Standards Commission pursuant to License Agreement. No further reproductions is authorized. Any unauthorized reproduction or distribution is a violation of the federal copyright act and the license agreement, and subject to civil and criminal penalties thereunder.

APPENDIX C—GUIDELINES FOR THE WIND RETROFIT OF EXISTING BUILDINGS

FASTENER SPACING FOR LUMBER TO LUMBER

CONNECTIONS OPERATING IN SHEAR PARALLEL TO GRAIN

END DISTANCE MINIMUM 2¹/�″

EDGE DISTANCE MINIMUM ¹/�″

MINIMUM 2¹/�″

For SI: 1 inch = 25.4 mm.

[BS] FIGURE C103.5.3 FASTENER SPACINGS FOR LUMBER-TO-LUMBER CONNECTIONS OPERATING IN SHEAR PARALLEL TO GRAIN

[BS] C103.5.3.1 General fastener spacing. Fastener spacing shall meet the following conditions except as provided for in Section C103.5.3.

The distance between fasteners and the edge of lumber that is less than 3 1 /2 inches deep (89 mm) in the direction of the fastener length shall be not less than 3 /4 inch (19.1 mm).

  1. The distance between fasteners and the edge of lumber that is more than 2 inches (51 mm) thick in the direction of the fastener length shall be not less than 1 /2 inch (12.7 mm).
  2. The distance between a fastener and the end of lumber shall be not less than 2 1 /2 inches (64 mm).
  3. The distance between fasteners parallel to the grain (center-to-center) shall be not less than 2 1 /2 inches (64 mm).
  4. The distance between fasteners perpendicular to the grain (center-to-center) in lumber that is less than 3 1 /2 inches (89 mm) deep in the direction of the fastener length shall be 1 inch (25 mm).
  5. The distance between fasteners perpendicular to the grain (center-to-center) in lumber that is more than 2 inches (51 mm) thick in the direction of the fastener length shall be 1 /2 inch (12.7 mm).

[BS] C103.5.3.2 Wood-to-wood connections of two members each 2 inches or less in thickness. Woodto-wood connections fastener spacing shall meet the following conditions.

  1. The distance between fasteners parallel to grain (center-to-center) shall be not less than 2 1 /2 inches (64 mm).

  2. The distance between fasteners across grain (center-to-center) shall be not less than 1 inch (25 mm).

  3. For wood-to-wood connections of lumber at right angles, fasteners shall be spaced not less than 2 1 /2 inches (64 mm) parallel to the grain and 1 inch (25 mm) perpendicular to the grain in any direction.

[BS] C103.5.3.3 Metal connectors for wood-to-wood connections. Metal connectors for wood-to-wood connections shall meet the following conditions.

  1. Fastener spacing to edge or ends of lumber shall be as dictated by the prefabricated holes in the connectors and the connectors shall be installed in a configuration that is similar to that shown by the connector manufacturer.
  2. Fasteners in 1 1 /4-inch-wide (32 mm) metal straps that are installed on the narrow face of lumber shall be a minimum 1 /4 inch (6.4 mm) from either edge of the lumber. Consistent with Section C103.5.3.1, fasteners shall be permitted to be spaced according to the fastener holes fabricated into the strap.
  3. Fasteners in metal nail plates shall be spaced not less than 1 /2 inch (12.7 mm) perpendicular to grain and not less than 1 1 /2 inches (38 mm) parallel to grain.

Copyright © 2022 by, or licensed to, International Code Council, Inc. (ALL RIGHTS RESERVED); licensed to California Building Standards Commission pursuant to License Agreement. No further reproductions is authorized. Any unauthorized reproduction or distribution is a violation of the federal copyright act and the license agreement, and subject to civil and criminal penalties thereunder.

APPENDIX C—GUIDELINES FOR THE WIND RETROFIT OF EXISTING BUILDINGS

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▸Contents — California Existing Building Code (Title 24, Part 10)
California Existing Building Code (Title 24, Part 10)
  1. Chapter 2 — DEFINITIONS
  2. Appendix A — GUIDELINES FOR
  3. Appendix B — SUPPLEMENTARY
  4. Appendix C — GUIDELINES FOR THE WIND
  5. Appendix D — BOARD OF
  6. Chapter 1 — SCOPE AND ADMINISTRATION
  7. Chapter 3 — PROVISIONS FOR ALL COMPLIANCE METHODS
  8. Chapter 4 — REPAIRS
  9. Chapter 5 — PRESCRIPTIVE COMPLIANCE METHOD
  10. Chapter 6 — CLASSIFICATION OF WORK
  11. Chapter 7 — ALTERATIONS—LEVEL 1
  12. Chapter 8 — ALTERATIONS—LEVEL 2
  13. Chapter 9 — ALTERATIONS—LEVEL 3
  14. Chapter 10 — CHANGE OF OCCUPANCY
  15. Chapter 11 — ADDITIONS
  16. Chapter 12 — HISTORIC BUILDINGS
  17. Chapter 13 — PERFORMANCE COMPLIANCE METHODS
  18. Chapter 14 — RELOCATED OR MOVED BUILDINGS
  19. Chapter 15 — CONSTRUCTION SAFEGUARDS
  20. ▸Chapter 16 — REFERENCED STANDARDS
    Overview
    1. Section A100
    2. Section A101
    3. Section A102
    4. Section A103
    5. Section A104
    6. Section A105
    7. Section A106
    8. Section A107
    9. Section A108
    10. Section A109
    11. Section A110
    12. Section A111
    13. Section A112
    14. Section A113
    15. Section A114
    16. Section A201
    17. Section A202
    18. Section A203
    19. Section A204
    20. Section A205
    21. Section A206
    22. Section A207
    23. Section A301
    24. Section A302
    25. Section A303
    26. Section A304
    27. Section A401
    28. Section A403
    29. Section A402
    30. Section A404
    31. Section A405
    32. Section A406
    33. Section A407
    34. Section A501
    35. Section B101
    36. Section B102
    37. Section B103
    38. Section B104
    39. Section C101
    40. Section C102
    41. Section C103
    42. Section C104
    43. Section C201
    44. Section C202
    45. Section C301
    46. Section D101

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