CBC · California Building Code

When is structural observation required and what does it include?

Structural observation under the CBC means the owner must hire a licensed design professional to visually observe representative structural elements when one of the triggers in §1704.6.1 applies (Risk Category III/IV, high‑rise, SDC E >2 stories, or on the RDP/building official’s direction). The observer must submit a pre‑start statement of frequency and extent and a concluding statement documenting visits and unresolved issues; this observation supplements but does not replace inspections in Section 110 or special inspections in Section 1705 (§1704.6; §1704.6.1) .

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Last reviewed: July 5, 2026

What the code requires — 2-4 sentences

The California Building Code requires the owner to employ a registered design professional to perform structural observation where the conditions listed in §1704.6.1 apply. Structural observation consists of visual observation of representative locations of structural systems, details and load paths to verify general conformance to the approved construction documents and confirmation of existing conditions assumed during design (§1704.6) . The structural observer must submit a written statement to the building official before observations begin describing the frequency and extent of observations, and a concluding statement identifying that site visits were made and any unresolved deficiencies (§1704.6) .

Requirements in detail

Who must be engaged

  • The owner (or the owner’s authorized agent) must employ a registered design professional to act as the structural observer (§1704.6) .

What structural observation is and what it does

  • Visual observation of representative locations of structural systems, details and load paths to check general conformance with the approved construction documents and to confirm existing conditions assumed in the design (§1704.6) .
  • Structural observation does NOT replace or waive the building official’s inspections under Section 110 or special inspections required in Section 1705 (§1704.6) .

When it is required (triggers)

Structural observations are required where one or more of these conditions exist (§1704.6.1) :

  1. Structure is classified Risk Category III or IV.
  2. Structure is a high-rise building.
  3. Structure is in Seismic Design Category E and is greater than two stories above grade plane.
  4. Structural observation is required by the registered design professional responsible for structural design.
  5. Structural observation is specifically required by the building official.

(For seismic retrofit projects, the California Existing Building Code highlights that structural observation is required regardless of SDC for many retrofit scopes — see Appendix A references such as A105.4 and A407.1) .

Required documentation and submittals

  • Pre‑start: the structural observer must submit a written statement to the building official identifying the frequency and extent of structural observations (§1704.6) .
  • Closeout: at project completion the structural observer must submit a written statement that the site visits have been made and identify any known unresolved deficiencies (§1704.6) .
  • Structural observation reports are distinct from the statement of special inspections required when special inspections/tests are triggered (see §1704.3 / §1704.2 and Section 1705 requirements) .

Decision-relevant dimensions (quick reference table)

Decision dimension Typical values / action Code reference
Who performs observation Registered design professional employed by owner §1704.6
Primary triggers (any one suffices) Risk Category III/IV; high‑rise; SDC E & >2 stories; RDP requires; building official requires §1704.6.1 (1–5)
Scope of observation Visual observation of representative structural locations, details and load paths; confirm assumed existing conditions §1704.6
Documentation required Pre-start statement of frequency & extent; concluding statement of visits and unresolved deficiencies §1704.6
Relationship to other inspections Does not replace Section 110 inspections or Section 1705 special inspections §1704.6
Additional retrofit requirement Existing Building Code often mandates structural observation regardless of SDC for seismic retrofit work Appendix A (A105.4, A407.1)

Exceptions & special cases

  • The CBC language lists no general numeric exception to §1704.6.1’s triggers; however, items (4) and (5) explicitly allow the registered design professional or the building official to require structural observation even when other triggers are not present (§1704.6.1(4–5)) .
  • For seismic retrofit projects, Appendix A of the Existing Building Code includes mandatory structural observation language that can be broader than the Chapter 17 triggers (structural observation "is required, regardless of seismic design category" for retrofit under those appendices) .
  • Structural observation is limited to visual observation and confirmation of assumed existing conditions; it is not a substitute for required testing or special inspections under Section 1705 or other specialized inspection programs (§1704.6) .

Common mistakes

  • Treating structural observation as the same thing as special inspections: structural observation is performed by a registered design professional and is visual/representative; special inspections (§1705) are separate and may be continuous, periodic or by testing agencies as required by the code (§1704.6 and §1705) .
  • Failing to submit the required pre‑start written statement of frequency and extent, or failing to provide the concluding statement at project end — both are explicit CBC requirements (§1704.6) .
  • Assuming the code prescribes a specific number of visits: §1704.6 requires the observer to identify the frequency and extent, but does not prescribe a single numeric protocol — that is established by the registered design professional in the submitted statement and by project-specific conditions (§1704.6) .
  • Not recognizing retrofit-specific mandates: retrofit provisions in the Existing Building Code can require observation even when Chapter 17 triggers might not apply — check applicable Appendix A requirements for retrofit projects .

Worked example — concrete scenario applying the rule with numbers

Scenario: A 5‑story office building (typical occupancy) located in an area assigned Seismic Design Category E. The building is >2 stories above grade.

  1. Which rule applies? Because the structure is in SDC E and is greater than two stories above grade plane, structural observation is required per §1704.6.1(3) (§1704.6.1) .
  2. Who must be engaged? The owner must hire a registered design professional to act as the structural observer (§1704.6) .
  3. What documentation is needed before work begins? The structural observer submits a written statement to the building official describing the frequency and extent of observations. Example (reasonable, illustrative): the RDP proposes 6 visits — footing inspection, foundation backfill, first‑floor diaphragm nailing/collector connections, shear wall/sheathing nailing at floors 2–4 (sampling), final structural framing review, and a final close‑out visit — and records representative locations to be observed (foundations, collectors, hold‑downs, moment connections). The CBC requires the pre‑start statement but does not mandate exactly “6”; the number comes from the RDP’s professional judgment (§1704.6) .
  4. What happens at completion? The structural observer submits the concluding written statement that the site visits were made and identifies any unresolved deficiencies (§1704.6) .
  5. Note: any required special inspections under Section 1705 (for example, welding, concrete, hold‑down anchor testing) must still be arranged and reported separately — structural observation does not waive those obligations (§1704.6; §1705) .

Related provisions

  • §1704.6 Structural observations (controlling)
  • §1704.6.1 Structural observations for structures (triggers)
  • §1704.1 General (scope for special inspections and structural observation)
  • Section 1705 — Required special inspections and tests (relationship to structural observation)
  • Section 110 — Building official inspections (structural observation does not replace these)
  • California Existing Building Code Appendix A (A105.4, A407.1) — seismic retrofit provisions that require structural observation regardless of SDC for retrofit work

Code references

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

  • CBC § 1704.6 High relevance — show source text

    SECTION A407—QUALITY CONTROL

    [BS] A407.1 Structural observation. Structural observation, in accordance with Section 1704.6 of the California Building Code is required, regardless of seismic design category, height or other conditions. Structural observation shall include visual observation of work for conformance to the approved construction documents and confirmation of existing conditions assumed during design.

    A407.2 Contractor responsibility. Contractor responsibility shall be in accordance with Section 1704.4 of the California Building Code .

    A407.3 Testing and inspection. Structural testing and inspection for new construction materials, submittals, reports and certificates of compliance shall be in accordance with Sections 1704 and 1705 of the California Building Code . Work done to comply with this chapter shall not be eligible for Exceptions 1, 2, or 3 of Section 1704.2 of the California Building Code or for the exception to Section 1705.13.2 of the California Building Code .

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    CALIFORNIA EXISTING BUILDING CODE – MATRIX ADOPTION TABLE

    APPENDIX A

    CHAPTER A5 – REFERENCED STANDARDS

    (Matrix Adoption Tables are nonregulatory, intended only as an aid to the code user. See Chapter 1 for state agency authority and building applications.)

    Adopting Agency BSC BSC-
    CG    		 SFM HCD Col6 Col7 DSA Col9 Col10 OSHPD Col12 Col13 Col14 Col15 Col16 Col17 BSCC DPH AGR DWR CEC CA SL SLC
    Adopting Agency BSC BSC-
    CG    		 SFM 1 2 1/AC AC SS SS/CC 1 1R 2 3 4 5 6 6 6 6 6 6 6 6 6
    Adopt Entire Chapter X X X
    Adopt Entire Chapter as
    amended (amended
    sections listed below)
    Adopt only those sections
    that are listed below
    Chapter / Section

    The state agency does not adopt sections identified with the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.

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  • CBC § 1705.14.3. High relevance — show source text
    1. Certificates of compliance for designated seismic systems in accordance with Section 1705.14.3.
    2. Reports of preconstruction tests for shotcrete in accordance with ACI 318.
    3. Certificates of compliance for open web steel joists and joist girders in accordance with Section 2207.5.
    4. Reports of material properties verifying compliance with the requirements of AWS D1.4 for weldability as specified in Section 26.6.4 of ACI 318 for reinforcing bars in concrete complying with a standard other than ASTM A706 that are to be welded.
    5. Reports of mill tests in accordance with Section 20.2.2.5 of ACI 318 for reinforcing bars complying with ASTM A615 and used to resist earthquake-induced flexural or axial forces in the special moment frames, special structural walls or coupling beams connecting special structural walls of seismic force-resisting systems in structures assigned to Seismic Design Category B, C, D, E or F.

    1704.6 Structural observations. Where required by the provisions of Section 1704.6.1, the owner or the owner’s authorized agent shall employ a registered design professional to perform structural observations. The structural observer shall visually observe representative locations of structural systems, details and load paths for general conformance to the approved construction documents. Structural observation does not include or waive the responsibility for the inspections in Section 110 or the special inspections in Section 1705 or other sections of this code. Prior to the commencement of observations, the structural observer shall submit to the building official a written statement identifying the frequency and extent of structural observations. At the conclusion of the work included in the permit, the structural observer shall submit to the building official a written statement that the site visits have been made and identify any reported deficiencies that, to the best of the structural observer’s knowledge, have not been resolved.

    1704.6.1 Structural observations for structures. Structural observations shall be provided for those structures where one or more of the following conditions exist:

    1. The structure is classified as Risk Category III or IV.
    2. The structure is a high-rise building.
    3. The structure is assigned to Seismic Design Category E, and is greater than two stories above grade plane.
    4. Such observation is required by the registered design professional responsible for the structural design.
    5. Such observation is specifically required by the building official.

    SECTION 1705—REQUIRED SPECIAL INSPECTIONS AND TESTS

    1705.1 General. Special inspections and tests of elements and nonstructural components of buildings and structures shall meet the applicable requirements of this section.

    1705.1.1 Special cases. Special inspections and tests shall be required for proposed work that is, in the opinion of the building official, unusual in its nature, such as, but not limited to, the following examples:

    1. Construction materials and systems that are alternatives to materials and systems prescribed by this code.
    2. Unusual design applications of materials described in this code.
    3. Materials and systems required to be installed in accordance with additional manufacturer’s instructions that prescribe requirements not contained in this code or in standards referenced by this code.

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    SPECIAL INSPECTIONS AND TESTS

    1705.2 Steel construction. The special inspections and nondestructive testing of steel construction in buildings, structures and portions thereof shall be in accordance with this section.

  • CBC § 1704.6 High relevance — show source text

    [BS] WALL SEGMENT. Any length of concrete wall with continuous horizontal reinforcing and not interrupted or intersected by a pilaster or vertical construction joint, or any length of reinforced masonry wall with continuous horizontal reinforcing and not interrupted or intersected by a pilaster or vertical control joint.

    SECTION A204—SYMBOLS AND NOTATIONS

    [BS] A204.1 General. For the purpose of this chapter, the applicable symbols and notations in the California Building Code shall apply.

    SECTION A205—GENERAL REQUIREMENTS

    [BS] A205.1 General. The seismic-resisting elements specified in this chapter shall comply with applicable provisions of Section 1613 of the California Building Code and Chapter 12 of ASCE 7, except as modified herein.

    [BS] A205.2 Requirements for plans. The plans shall accurately reflect the results of the engineering investigation and design and shall show all pertinent dimensions and sizes for plan review and construction. The following shall be provided:

    1. Floor plans and roof plans shall show existing framing construction, diaphragm construction, proposed wall anchors, crossties and collectors. Existing nailing, anchors, crossties and collectors shall be shown on the plans if they are considered part of the lateral force-resisting systems.
    2. Typical wall panel details and sections with panel thickness, height, pilasters and location of anchors shall be provided.
    3. Details shall include existing and new anchors and the method of developing anchor forces into the diaphragm framing, existing and new crossties, and existing and new or improved support of roof and floor girders at pilasters or walls.
    4. The basis for design and the building code used for the design shall be stated on the plans.

    [BS] A205.3 Structural observation. Structural observation, in accordance with Section 1704.6 of the California Building Code is required, regardless of seismic design category, height or other conditions. Structural observation shall include visual observation of work for conformance to the approved construction documents and confirmation of existing conditions assumed during design.

    A205.3.1 Additional special inspection. In addition to the requirements of Section 1705.13 of the California Building Code, special inspection shall be required for:

    1. Installation of anchors into existing concrete or masonry walls to form part of a wall anchorage system.

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    APPENDIX A—GUIDELINES FOR THE SEISMIC RETROFIT OF EXISTING BUILDINGS

    1. Fastening of new or existing steel deck forming part of a wall anchorage system.
    2. Installation of continuity connectors along the length of crossties, to ensure compliance with Section A206.2. This inspection may be periodic special inspection.

    A205.3.2 Testing to establish adequacy of existing wall anchors. Testing shall show that the existing anchors can sustain a test load of 1.5 times the design tension load without noticeable deformation or damage to the anchor, to the masonry or concrete element, or to any part of the existing load path between the anchor and new retrofit components. Three anchors of each existing detail type shall be tested, and all three shall satisfy the requirement. Prior to testing, the design professional shall submit a test plan for code official approval identifying the expected locations of the existing anchors in question, the locations of the proposed tests, and the test procedure and criteria.

  • CBC § 1704.6.1 High relevance — show source text

    1704.6.1 Structural observations for structures. Structural observations shall be provided for those structures where one or more of the following conditions exist:

    1. The structure is classified as Risk Category III or IV.
    2. The structure is a high-rise building.
    3. The structure is assigned to Seismic Design Category E, and is greater than two stories above grade plane.
    4. Such observation is required by the registered design professional responsible for the structural design.
    5. Such observation is specifically required by the building official.

    SECTION 1705—REQUIRED SPECIAL INSPECTIONS AND TESTS

    1705.1 General. Special inspections and tests of elements and nonstructural components of buildings and structures shall meet the applicable requirements of this section.

    1705.1.1 Special cases. Special inspections and tests shall be required for proposed work that is, in the opinion of the building official, unusual in its nature, such as, but not limited to, the following examples:

    1. Construction materials and systems that are alternatives to materials and systems prescribed by this code.
    2. Unusual design applications of materials described in this code.
    3. Materials and systems required to be installed in accordance with additional manufacturer’s instructions that prescribe requirements not contained in this code or in standards referenced by this code.

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    SPECIAL INSPECTIONS AND TESTS

    1705.2 Steel construction. The special inspections and nondestructive testing of steel construction in buildings, structures and portions thereof shall be in accordance with this section.

    Exception: Special inspections of the steel fabrication process shall not be required where the fabrication process for the entire building or structure does not include any welding, thermal cutting or heating operation of any kind. In such cases, the fabricator shall be required to submit a detailed procedure for material control that demonstrates the fabricator’s ability to maintain suitable records and procedures such that, at any time during the fabrication process, the material specification and grade for the main stress-carrying elements are capable of being determined. Mill test reports shall be identifiable to the main stress-carrying elements where required by the approved construction documents.

    1705.2.1 Structural steel. Special inspections and nondestructive testing of structural steel elements in buildings, structures and portions thereof shall be in accordance with the quality assurance inspection requirements of AISC 360. [OSHPD 1R, 2 & 5] and this code.

    Exception: Special inspection of railing systems composed of structural steel elements shall be limited to welding inspection of welds at the base of cantilevered rail posts.

    [OSHPD 1R, 2 & 5] The following provisions of AISC 360, Chapter N are not permitted: 1. N5, Item 3 (Coordinated Inspection). 2. N6 (Approved Fabricators and Erectors).

    Notes: [OSHPD 1R, 2 & 5]

  • CBC § 5.3 High relevance — show source text
    1. The type of interior wall and ceiling materials, and framing.
    2. The extent and type of existing wall anchorage to floors and roof where used in the design.
    3. The extent and type of parapet corrections that were previously performed, if any.
    4. Repair details, if any, of cracked or damaged unreinforced masonry walls required to resist forces specified in this chapter.
    5. All other plans, sections and details necessary to delineate required retrofit construction.
    6. The design procedure used shall be stated on both the plans and the permit application.
    7. Details of the anchor prequalification program required by Section A107.5.3, if used, including location and results of all tests.
    8. Quality assurance requirements of special inspection for all new construction materials and for retrofit construction including: anchor tests, pointing or repointing of mortar joints, installation of adhesive or mechanical anchors, and other elements as deemed necessary to ensure compliance with this chapter.

    [BS] A105.4 Structural observation, testing and inspection. Structural observation, in accordance with Section 1704.6 of the Cali- fornia Building Code, shall be required for all structures in which seismic retrofit is being performed in accordance with this chapter. Structural observation shall include visual observation of work for compliance with the approved construction documents and confirmation of existing conditions assumed during design. Structural testing and inspection for new and existing construction materials shall be in accordance with the building code, except as modified by this chapter. Special inspection as described in Section A105.3, Item 10, shall be provided equivalent to Level 3 as prescribed in TMS 402, Table 3.1(2).

    SECTION A106—MATERIALS REQUIREMENTS

    [BS] A106.1 Condition of existing materials. Existing materials used as part of the required vertical load-carrying or seismic forceresisting system shall be evaluated by on-site investigation and: determined to be in good condition (free of degraded mortar, degraded masonry units or significant cracking); or shall be repaired, enhanced, retrofitted or removed and replaced with new materials. Mortar joint deterioration shall be patched by pointing or repointing of the eroded joint in accordance with Section A106.2.3.10. Existing significant cracks in solid unit unreinforced and solid grouted hollow unit masonry shall be repaired.

    [BS] A106.2 Existing unreinforced masonry.

    [BS] A106.2.1 General. Unreinforced masonry walls used to support vertical loads or seismic forces parallel and perpendicular to the wall plane shall be tested as specified in this section. Masonry that does not meet the minimum requirements established by this chapter shall be repaired, enhanced, removed and replaced with new materials, or alternatively, shall have its structural functions replaced with new materials and shall be anchored to supporting elements.

    [BS] A106.2.2 Lay-up of walls. Unreinforced masonry walls shall be laid in a running bond pattern.

    [BS] A106.2.2.1 Header in multiple-wythe solid brick. The facing and backing wythes of multiple-wythe walls shall be bonded so that not less than 10 percent of the exposed face area is composed of solid headers extending not less than 4 inches (102 mm) into the backing wythes. The clear distance between adjacent header courses shall not exceed 24 inches (610 mm) vertically or horizontally.

  • CBC § 3.3 High relevance — show source text

    APPENDIX A—GUIDELINES FOR THE SEISMIC RETROFIT OF EXISTING BUILDINGS

    [BS] A406.3.3 Shear wall schedule, notes and details. Shear walls shall have a referenced schedule on the plans that includes the correct shear wall capacity in pounds per foot (N/m); the required fastener type, length, gage and head size; and a complete specification for the sheathing material and its thickness. The schedule shall also show the required location of 3-inch (76 mm) nominal or two 2-inch (51 mm) nominal edge members; the spacing of shear transfer elements such as framing anchors or added sill plate nails; the required hold-down with its bolt, screw or nail sizes; and the dimensions, lumber grade and species of the attached framing member.

    Notes shall show required edge distance for fasteners of structural wood panels and framing members; required flush nailing at the plywood surface; limits of mechanical penetrations; and the sill plate material assumed in the design. The limits of mechanical penetrations shall be detailed showing the maximum notching and drilled hole sizes.

    [BS] A406.3.4 General notes. General notes shall show the requirements for material testing, special inspection and structural observation.

    SECTION A407—QUALITY CONTROL

    [BS] A407.1 Structural observation. Structural observation, in accordance with Section 1704.6 of the California Building Code is required, regardless of seismic design category, height or other conditions. Structural observation shall include visual observation of work for conformance to the approved construction documents and confirmation of existing conditions assumed during design.

    A407.2 Contractor responsibility. Contractor responsibility shall be in accordance with Section 1704.4 of the California Building Code .

    A407.3 Testing and inspection. Structural testing and inspection for new construction materials, submittals, reports and certificates of compliance shall be in accordance with Sections 1704 and 1705 of the California Building Code . Work done to comply with this chapter shall not be eligible for Exceptions 1, 2, or 3 of Section 1704.2 of the California Building Code or for the exception to Section 1705.13.2 of the California Building Code .

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    CALIFORNIA EXISTING BUILDING CODE – MATRIX ADOPTION TABLE

    APPENDIX A

    CHAPTER A5 – REFERENCED STANDARDS

    (Matrix Adoption Tables are nonregulatory, intended only as an aid to the code user. See Chapter 1 for state agency authority and building applications.)

  • CBC § 2.3.9 High relevance — show source text

    Σ W d = Total dead load of all the diaphragms at and above the level under consideration, pounds (N).

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    APPENDIX A—GUIDELINES FOR THE SEISMIC RETROFIT OF EXISTING BUILDINGS

    SECTION A105—GENERAL REQUIREMENTS

    [BS] A105.1 General. The seismic force-resisting system specified in this chapter shall comply with the California Building Code and referenced standards, except as modified herein.

    [BS] A105.2 Alterations and repairs. Alterations and repairs required to meet the provisions of this chapter shall comply with applicable structural requirements of the building code unless specifically provided for in this chapter.

    [BS] A105.3 Requirements for plans. The following construction information shall be included in the plans required by this chapter:

    1. Dimensioned floor and roof plans showing existing walls and the size and spacing of floor and roof-framing members and sheathing materials. The plans shall indicate all existing URM walls, and new crosswalls and shear walls, and their materials of construction. The location of these walls and their openings shall be fully dimensioned and drawn to scale on the plans.
    2. Dimensioned URM wall elevations showing openings, piers, wall classes as defined in Section A106.2.3.9, thickness, heights, wall shear test locations, cracks or damaged portions requiring repairs, the general condition of the mortar joints, and if and where pointing is required. Where the exterior face is veneer, the type of veneer, its thickness and its bonding and/or ties to the structural wall masonry shall be noted.
    3. The type of interior wall and ceiling materials, and framing.
    4. The extent and type of existing wall anchorage to floors and roof where used in the design.
    5. The extent and type of parapet corrections that were previously performed, if any.
    6. Repair details, if any, of cracked or damaged unreinforced masonry walls required to resist forces specified in this chapter.
    7. All other plans, sections and details necessary to delineate required retrofit construction.
    8. The design procedure used shall be stated on both the plans and the permit application.
    9. Details of the anchor prequalification program required by Section A107.5.3, if used, including location and results of all tests.
    10. Quality assurance requirements of special inspection for all new construction materials and for retrofit construction including: anchor tests, pointing or repointing of mortar joints, installation of adhesive or mechanical anchors, and other elements as deemed necessary to ensure compliance with this chapter.

    [BS] A105.4 Structural observation, testing and inspection. Structural observation, in accordance with Section 1704.6 of the Cali- fornia Building Code, shall be required for all structures in which seismic retrofit is being performed in accordance with this chapter. Structural observation shall include visual observation of work for compliance with the approved construction documents and confirmation of existing conditions assumed during design. Structural testing and inspection for new and existing construction materials shall be in accordance with the building code, except as modified by this chapter. Special inspection as described in Section A105.3, Item 10, shall be provided equivalent to Level 3 as prescribed in TMS 402, Table 3.1(2).

    SECTION A106—MATERIALS REQUIREMENTS

  • CBC § 3.1 High relevance — show source text

    [BS] A406.2 Existing construction. The plans shall show existing diaphragm and shear wall sheathing and framing materials; fastener type and spacing; diaphragm and shear wall connections; continuity ties; collector elements; and the portion of the existing materials that needs verification during construction. If the cap allowed by Section A403.3.1 is used to limit the scope of retrofit, the foregoing information shall be shown for each retrofitted story and at least one story above the uppermost retrofitted story. If the cap allowed by Section A403.3.1 is not used, the foregoing information need only be shown for each retrofitted story and for the floor at the top of that story.

    [BS] A406.3 New construction.

    [BS] A406.3.1 Foundation plan elements. The foundation plan shall include the size, type, location and spacing of all anchor bolts with the required depth of embedment, edge and end distance; the location and size of all shear walls and all columns for braced frames or moment frames; referenced details for the connection of shear walls, braced frames or moment-resisting frames to their footing; and referenced sections for any grade beams and footings.

    [BS] A406.3.2 Framing plan elements. The framing plan shall include the length, location and material of shear walls; the location and material of frames; references or details for the column-to-beam connectors, beam-to-wall connections and shear transfers at floor and roof diaphragms; and the required nailing and length for wall top plate splices.

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    APPENDIX A—GUIDELINES FOR THE SEISMIC RETROFIT OF EXISTING BUILDINGS

    [BS] A406.3.3 Shear wall schedule, notes and details. Shear walls shall have a referenced schedule on the plans that includes the correct shear wall capacity in pounds per foot (N/m); the required fastener type, length, gage and head size; and a complete specification for the sheathing material and its thickness. The schedule shall also show the required location of 3-inch (76 mm) nominal or two 2-inch (51 mm) nominal edge members; the spacing of shear transfer elements such as framing anchors or added sill plate nails; the required hold-down with its bolt, screw or nail sizes; and the dimensions, lumber grade and species of the attached framing member.

    Notes shall show required edge distance for fasteners of structural wood panels and framing members; required flush nailing at the plywood surface; limits of mechanical penetrations; and the sill plate material assumed in the design. The limits of mechanical penetrations shall be detailed showing the maximum notching and drilled hole sizes.

    [BS] A406.3.4 General notes. General notes shall show the requirements for material testing, special inspection and structural observation.

    SECTION A407—QUALITY CONTROL

    [BS] A407.1 Structural observation. Structural observation, in accordance with Section 1704.6 of the California Building Code is required, regardless of seismic design category, height or other conditions. Structural observation shall include visual observation of work for conformance to the approved construction documents and confirmation of existing conditions assumed during design.

    A407.2 Contractor responsibility. Contractor responsibility shall be in accordance with Section 1704.4 of the California Building Code .

  • CBC § 319.9 High relevance — show source text

    Exception: A component’s strength is permitted to be less than that required by the specified seismic load combinations if it can be demonstrated that the associated reduction in seismic performance of the component or its removal due to the failure does not result in a structural system that does not comply with the required performance objectives of Section 317. If this exception is taken for a component, then it cannot be considered part of the primary lateral-load-resisting system.

    319.9 Nonstructural component requirements. Where the nonstructural performance levels required by Section 317, Table 317.5 are N-D or higher, mechanical, electrical and plumbing components shall comply with the provisions of ASCE 41, Chapter 13, Section 13.2.

    Exception: Modifications to the procedures and criteria may be made subject to approval by the building official, and concurrence of the peer reviewer if applicable. All reports and correspondence shall also be forwarded to the building official.

    319.10 Structural observation, testing and inspection. Structural observation, testing and inspection as used in this section shall mean meeting the requirements of Chapter 17 of the California Building Code, with a minimum allowable level of investigation corresponding to seismic design category (SDC) D. Structural observation visits shall occur at significant construction stages and at the completion of the structural retrofit. Structural observation shall be provided for all structures.

    Additional requirements: [DSA-SS, DSA-SS/CC] For public schools and community colleges, construction material testing, inspection and observation during construction shall also comply with the California Administrative Code.

    319.10.1 The requirement for structural observation shall be noted and prominently displayed on the front sheet of the approved plans and incorporated into the general notes on the approved plans.

    319.10.2 Preconstruction meeting. A preconstruction meeting is mandatory for all projects which require structural observation. The meeting shall include, but is not limited to, the registered design professional, structural observer, general constructor, affected subcontractors, the project inspector and a representative of the enforcement agency (designated alternates may attend if approved by the structural observer). The structural observer shall schedule and coordinate this meeting. The purpose of the meeting is to identify and clarify all essential structural components and connections that affect the lateral and vertical load systems and to review scheduling of the required observations for the project’s structural system retrofit.

    319.11 Temporary actions. When compatible with the building use, and the time phasing for both use and the retrofit program, temporary shoring or other structural support is permitted to be considered. Temporary bracing, shoring and prevention of falling hazards are permitted to be used to qualify for Item 1 in Section 319.12 that allows inadequate capability in some existing components, as long as the required performance levels given in Section 317 can be provided by the permanent structure. The consideration for such temporary actions shall be noted in the design documents.

    319.12 Voluntary modifications to the lateral-force resisting system. Where modifications of existing structural components and additions of new structural components are initiated for the purpose of improving the lateral-force resisting strength or stiffness of an existing structure and they are not required by other sections of this code, then they are permitted to be designed to meet an approved seismic performance criteria provided that an engineering analysis is submitted that follows: 1. The capacity of existing structural components required to resist forces is not reduced, unless it can be demonstrated that

  • CBC § 319.7.1 High relevance — show source text

    319.7.1 A building with prestressed or post- tensioned structural components (beams, columns, walls or slabs) or precast structural components (beams, columns, walls or flooring systems).

    319.7.2 A building classified as irregular per Section 319.5.

    Exceptions: 1. The retrofit design removes the configurational attributes that caused the building to be classified as irregular. 2. The irregularity is demonstrated not to affect the seismic performance of the building.

    319.7.3 A building assigned to Risk Category IV per Section 319.4.

    319.7.4 A building with an undefined or hybrid structural system.

    2025 CALIFORNIA EXISTING BUILDING CODE 3-19

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

    PROVISIONS FOR ALL COMPLIANCE METHODS

    319.7.5 A building with a seismic isolation or energy dissipation system, either as part of the existing structure or as part of the retrofit.

    319.7.6 A building greater than 240 feet (73 m) in height.

    319.7.7 A building evaluated per ASCE 41 and its application requires the use of a nonlinear analysis procedure.

    319.8 Strength requirements. All components of the lateral-force-resisting system must have the strength to meet the acceptance criteria prescribed in ASCE 41, Chapter 7 or as prescribed in the applicable Appendix A chapter of this code if a specific procedure in Section 319.1.1 is used. Any component not having this strength shall have its capacity increased by modifying or supplementing its strength so that it exceeds the demand, or the demand is reduced to less than the existing strength by making other modifications to the structural system.

    Exception: A component’s strength is permitted to be less than that required by the specified seismic load combinations if it can be demonstrated that the associated reduction in seismic performance of the component or its removal due to the failure does not result in a structural system that does not comply with the required performance objectives of Section 317. If this exception is taken for a component, then it cannot be considered part of the primary lateral-load-resisting system.

    319.9 Nonstructural component requirements. Where the nonstructural performance levels required by Section 317, Table 317.5 are N-D or higher, mechanical, electrical and plumbing components shall comply with the provisions of ASCE 41, Chapter 13, Section 13.2.

    Exception: Modifications to the procedures and criteria may be made subject to approval by the building official, and concurrence of the peer reviewer if applicable. All reports and correspondence shall also be forwarded to the building official.

    319.10 Structural observation, testing and inspection. Structural observation, testing and inspection as used in this section shall mean meeting the requirements of Chapter 17 of the California Building Code, with a minimum allowable level of investigation corresponding to seismic design category (SDC) D. Structural observation visits shall occur at significant construction stages and at the completion of the structural retrofit. Structural observation shall be provided for all structures.

    Additional requirements: [DSA-SS, DSA-SS/CC] For public schools and community colleges, construction material testing, inspection and observation during construction shall also comply with the California Administrative Code.

  • CBC § 2.4 High relevance — show source text

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

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    SPECIAL INSPECTIONS AND TESTS

    1704 A .4 Contractor responsibility. Each contractor responsible for the construction of a main wind- or seismic force-resisting system, installation of equipment/components requiring special seismic certification or a wind- or seismic force-resisting component listed in the statement of special inspections shall submit a written statement of responsibility to the building official and the owner or the owner’s authorized agent prior to the commencement of work on the system or component. The contractor’s statement of responsibility shall contain acknowledgement of awareness of the special requirements contained in the statement of special inspections. [DSA-SS, DSA-SS/CC] The contractor’s statement is required only when specified on the approved construction documents.

    1704 A .5 Submittals to the building official. In addition to the submittal of reports of special inspections and tests in accordance with Section 1704 A .2.4, reports and certificates shall be submitted by the owner or the owner’s authorized agent to the building official for each of the following:

    1. Reserved.

    2. Reserved.

    3. Certificates of compliance for equipment/components requiring special seismic certification in accordance with Section 1705 A .14.3.

    4. Reports of preconstruction tests for shotcrete in accordance with ACI 318 and Section 1705A.3.9.2.

    5. Certificates of compliance for open web steel joists and joist girders in accordance with Section 2207 A. 5.

    6. Reports of material properties verifying compliance with the requirements of AWS D1.4 for weldability as specified in Section 26.6.4 of ACI 318 for reinforcing bars in concrete complying with a standard other than ASTM A706 that are to be welded.

    7. Reports of mill tests in accordance with Section 20.2.2.5 of ACI 318 for reinforcing bars complying with ASTM A615 and used to resist earthquake-induced flexural or axial forces in the special moment frames, special structural walls or coupling beams connecting special structural walls of seismic force-resisting systems in structures assigned to Seismic Design Category D, E or F.

    1704 A .6 Structural observations. The owner shall employ a registered design professional to perform structural observations. The structural observer shall visually observe representative locations of structural systems, details and load paths for general conformance to the approved construction documents. Structural observation does not include or waive the responsibility for the inspections in Section 110 or the special inspections in Section 1705 A or other sections of this code. Prior to the commencement of observations, the structural observer shall submit to the building official a written statement identifying the frequency and extent of structural observations. At the conclusion of the work included in the permit, the structural observer shall submit to the building official a written statement that the site visits have been made and identify any reported deficiencies that, to the best of the structural observer’s knowledge, have not been resolved.

    [DSA-SS, DSA-SS/CC] Reference to Section 110 shall be to the California Administrative Code instead.

    SECTION 1705 A —REQUIRED SPECIAL INSPECTIONS AND TESTS

  • CBC § 26.6.4 High relevance — show source text
    1. Reports of material properties verifying compliance with the requirements of AWS D1.4 for weldability as specified in Section 26.6.4 of ACI 318 for reinforcing bars in concrete complying with a standard other than ASTM A706 that are to be welded.
    2. Reports of mill tests in accordance with Section 20.2.2.5 of ACI 318 for reinforcing bars complying with ASTM A615 and used to resist earthquake-induced flexural or axial forces in the special moment frames, special structural walls or coupling beams connecting special structural walls of seismic force-resisting systems in structures assigned to Seismic Design Category D, E or F.

    1704 A .6 Structural observations. The owner shall employ a registered design professional to perform structural observations. The structural observer shall visually observe representative locations of structural systems, details and load paths for general conformance to the approved construction documents. Structural observation does not include or waive the responsibility for the inspections in Section 110 or the special inspections in Section 1705 A or other sections of this code. Prior to the commencement of observations, the structural observer shall submit to the building official a written statement identifying the frequency and extent of structural observations. At the conclusion of the work included in the permit, the structural observer shall submit to the building official a written statement that the site visits have been made and identify any reported deficiencies that, to the best of the structural observer’s knowledge, have not been resolved.

    [DSA-SS, DSA-SS/CC] Reference to Section 110 shall be to the California Administrative Code instead.

    SECTION 1705 A —REQUIRED SPECIAL INSPECTIONS AND TESTS

    1705 A .1 General. Special inspections and tests of elements and nonstructural components of buildings and structures shall meet the applicable requirements of this section.

    1705 A .1.1 Special cases. Special inspections and tests shall be required for proposed work that is, in the opinion of the building official, unusual in its nature, such as, but not limited to, the following examples:

    1. Construction materials and systems that are alternatives to materials and systems prescribed by this code.
    2. Unusual design applications of materials described in this code.
    3. Materials and systems required to be installed in accordance with additional manufacturer’s instructions that prescribe requirements not contained in this code or in standards referenced by this code.

    1705 A .2 Steel construction. The special inspections and nondestructive testing of steel construction in buildings, structures and portions thereof shall be in accordance with this section.

    Exception: Special inspections of the steel fabrication process shall not be required where the fabrication process for the entire building or structure does not include any welding, thermal cutting or heating operation of any kind. In such cases, the fabricator shall be required to submit a detailed procedure for material control that demonstrates the fabricator’s ability to maintain suitable records and procedures such that, at any time during the fabrication process, the material specification and grade for the main stress-carrying elements are capable of being determined. Mill test reports shall be identifiable to the main stress-carrying elements where required by the approved construction documents.

    1705 A .2.1 Structural steel. Special inspections and nondestructive testing of structural steel elements in buildings, structures and portions thereof shall be in accordance with the quality assurance requirements of AISC 360 and this code.

Frequently asked questions

Who decides how often the structural observer must visit the site?

The registered design professional acting as the structural observer determines and documents the frequency and extent of visits in the pre‑start written statement submitted to the building official (§1704.6) .

Is structural observation the same as the special inspections in Section 1705?

No. Structural observation is a visual, registered‑design‑professional activity focused on representative structural features; special inspections under §1705 are separate, may be continuous or periodic, and are performed by approved agencies or qualified inspectors (§1704.6; §1705) .

Does the building official ever require structural observation even if triggers aren’t otherwise met?

Yes. §1704.6.1(5) allows the building official to specifically require structural observation, and §1704.6.1(4) allows the design professional to require it (§1704.6.1) .

For seismic retrofit projects, is observation always required?

Appendix A (Existing Building Code) contains provisions that require structural observation for many seismic retrofit projects regardless of seismic design category; verify applicable Appendix A sections for your retrofit scope (see A105.4, A407.1) .

What must the structural observer report at the end of the job?

A written statement to the building official that the site visits were made and identifying any reported deficiencies that, to the best of the observer’s knowledge, have not been resolved (§1704.6) .

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