CBC · California Building Code

When are special inspections required for wood and mass timber construction?

For homeowners: the CBC requires special inspections for certain on‑site wood work (like special diaphragms and long trusses), for factory manufacture of engineered wood (trusses, glulam, CLT), and for specific mass timber connections (Table 1705.5.3). Some items need an inspector on‑site the whole time (continuous); others are checked periodically. Your architect or structural engineer will list required inspections in the statement of special inspections submitted with the permit.

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Last reviewed: July 5, 2026

What the code requires — 2–4 sentences

Special inspections for wood construction are required where the California Building Code (CBC) specifically calls them out for site-built wood assemblies, high‑load diaphragms, long‑span metal‑plate trusses and certain manufactured wood products; the controlling CBC provision for site-built wood work is § 1705.5. For mass timber in Type IV construction (IV‑A, IV‑B, IV‑C) the required inspections are set out in Table 1705.5.3 (and the parallel Table 1705A.5.3 in the A (administrative) sections) and differentiate continuous versus periodic inspection depending on the item.

Requirements in detail

Scope — what § 1705.5 and Table 1705.5.3 cover

  • § 1705.5 directs special inspection for wood construction: site‑built assemblies follow § 1705.5’s requirements; prefabricated wood structural elements and assemblies are inspected per § 1704.2.5 (fabrication inspection) except as modified.
  • Mass timber elements in Type IV‑A, IV‑B and IV‑C are to be inspected in accordance with Table 1705.5.3 (CBC) or Table 1705A.5.3 (administrative version) which list the required continuous vs. periodic inspections for specific connection types, anchors and erection activities.

Decision table — common triggers and inspection types

Condition / trigger Inspection type required Code reference
Site‑built wood structural assemblies (general) Special inspection as specified in § 1705.5 § 1705.5; see CBC text
High‑load diaphragms (field gluing, sheathing, fasteners, etc.) Continuous for field gluing; periodic for fastening/fasteners § 1705.5.1
Metal‑plate‑connected wood trusses with clear span ≥ 60 ft (18 288 mm) Special inspector verification of temporary/permanent bracing (periodic field verification) § 1705.5.2 (60 ft / 18 288 mm)
Manufacture of trusses and similar assemblages (shop) Continuous inspection by an approved agency § 1705.5.4 (manufactured trusses)
Manufacture of structural glued‑laminated and cross‑laminated timber Continuous inspection (factory manufacture) § 1705.5.5 / § 1705A.5.5
Mass timber — anchorage & connections to timber deep foundations Periodic special inspection (Table 1705.5.3 / 1705A.5.3) Table 1705.5.3 / Table 1705A.5.3
Mass timber — erection of mass timber construction Periodic special inspection (erection) Table 1705.5.3 / 1705A.5.3
Mass timber — adhesive anchors installed horizontal or upward inclined to resist sustained tension Continuous special inspection Table 1705.5.3 / 1705A.5.3 (adhesive anchors horizontal/upward → continuous)
Mass timber — other adhesive anchors, bolted connections, threaded fasteners, concealed connections Periodic special inspection (per the table and subitems; e.g., inspect screws for diameter/length/spacing) Table 1705.5.3 / 1705A.5.3 and their subitems
Sealing of mass timber (sealants / adhesives required by § 703.7) Periodic special inspection where designated on the approved documents § 1705.20 / 1705A.20 (sealing of mass timber)

Notes on the table: the CBC splits inspection into Continuous (inspector present for the operation) vs Periodic (inspector observes and samples at intervals). The mass timber tables list specific items and subitems (threaded fasteners and their installation equipment, pre‑drilling, screw attributes; adhesive anchors; bolted and concealed connections) and identify which are continuous or periodic.

Who prepares and files the inspection plan

The registered design professional in responsible charge must prepare a statement of special inspections identifying what will be inspected, the extent (continuous vs periodic), tests required and any deferred items; that statement is a required submittal for permit per § 1704 (statement of special inspections requirements). Approved agencies must also keep reports and submit them as required.

Exceptions & special cases

  • Prefabricated / shop‑fabricated wood members: fabrication inspections are governed by § 1704.2.5 (special inspection of fabricated items) — shop fabrication is inspected during fabrication unless the fabricator is approved to work without special inspections under the code’s fabricator‑approval provisions.
  • Non‑custom, stock glulam members (specific size/span limits) may be excepted from special inspection for manufacture where the ANSI/APA A190.1 criteria are met (see exception to § 1705A.5.5). Read the exception carefully — it is limited to non‑custom prismatic members meeting the size/span/manufacturing standards.
  • DSA/OSHPD jurisdictions and administrative (A) chapters have parallel provisions (e.g., 1705A.5.3) and in some cases different reporting or prohibition of exceptions; always check whether the project is under a specialized jurisdiction.

If a required special inspection item is omitted from the statement of special inspections submitted with the permit, the building official can require it in the field; the code requires accessibility/exposure of the work for inspection until inspection is complete.

Common mistakes

  • Assuming "all wood" work needs special inspection. Only those assemblies and activities the code explicitly calls out (site‑built structural assemblies, certain diaphragms, long‑span trusses, manufactured products, and the specific mass timber items in Table 1705.5.3 / 1705A.5.3) are required. Check § 1705.5 and the tables rather than applying a blanket rule.
  • Confusing continuous vs periodic: continuous means the special inspector is present for the entire operation (e.g., some adhesive anchor installations), periodic means sampling/interval checks per the approved construction documents and table designations. Refer to the table entries for the correct classification.
  • Forgetting the fabrication pathway: prefabricated items are inspected under fabrication rules (§ 1704.2.5) which can differ from on‑site requirements.
  • Overlooking the statement of special inspections and report requirements — these are required submittals and form the basis for field inspection scope and reporting.

Worked example — applying the rule with numbers

Scenario: You are building a 4‑story Type IV‑B office building using cross‑laminated timber (CLT) floor panels and mass timber columns. The project uses adhesive anchors installed horizontally to resist sustained tension for some column anchorage. There are also a few bolted concealed connections and a manufactured glued‑laminated beam ordered from a mill.

How to determine required special inspections:

  1. Mass timber in Type IV‑B → follow Table 1705.5.3 (or 1705A.5.3). The table explicitly requires inspection of erection and anchorage/connection items. Plan for periodic inspection of erection and anchorage as shown in the table.
  2. Adhesive anchors installed horizontally to resist sustained tension are listed in the table as requiring continuous special inspection. That means schedule a special inspector to be present during those anchor installations. (Table item: adhesive anchors horizontal/upward → Continuous).
  3. Bolted and concealed connections: the table identifies these items as requiring periodic special inspection — plan sampling/verification during installation per the table subitems (verify bolt installation, torque, washers, concealed connection completion, etc.).
  4. The manufactured glulam beam: manufacture of structural glued laminated timber must be continuously inspected by an approved agency at the plant; confirm the fabricator’s continuous inspection report and that each member is identified per the approved agency’s report. If the beam is a non‑custom stock member that meets the exception criteria (e.g., within size/span limits and ANSI/APA A190.1 marking), the exception to special inspection manufacture may apply — otherwise expect continuous factory inspection.
  5. Prepare the statement of special inspections to list: CLT manufacture verification/plant inspection, continuous inspection for adhesive anchors in the field, periodic inspection of bolted/concealed connections and erection observation. Submit that with permit and coordinate inspector availability.

Related provisions (CBC sections you should read)

  • § 1705.5 — Wood construction (site‑built, high‑load diaphragms, long‑span trusses)
  • Table 1705.5.3 — Required special inspections of mass timber construction (CBC)
  • Table 1705A.5.3 — Required special inspections of mass timber construction (administrative/A version)
  • § 1705.5.1 — High‑load diaphragms (inspection scope)
  • § 1705.5.2 — Metal‑plate‑connected trusses spanning 60 ft (18 288 mm) or greater (inspection requirements)
  • § 1705.5.4 & § 1705.5.5 — Manufacture of trusses; manufacture of glued‑laminated and cross‑laminated timber (continuous inspection)
  • § 1704.2.5 / § 1704.3 — Statement of special inspections; fabricated item inspection (shop fabrication) and reporting requirements
  • § 1705.20 / § 1705A.20 — Sealing of mass timber (periodic inspection of sealants/adhesives where required)

Code references

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

  • CBC § 4.1 High relevance — show source text

    1705 A .4.1 Glass unit masonry and masonry veneer in Risk Category II, III or IV. Special inspections and tests for glass unit masonry or masonry veneer designed in accordance with Section 2110 A or Chapter 14, respectively, where they are part of a structure classified as Risk Category II, III or IV shall be performed in accordance with TMS 602 Tables 3 and 4, Level 2.

    1705A.4.1.1 TMS 602 Section 1.6 Quality Assurance. Replace footnote (d) in TMS 602 Table 4 as follows:

    (d) Periodic special inspection is required for all veneer.

    1705 A .4.2 Vertical masonry foundation elements. Special inspections and tests of vertical masonry foundation elements shall be performed in accordance with Section 1705 A .4.

    1705 A .5 Wood construction. Special inspections of prefabricated wood structural elements and assemblies shall be in accordance with Section 1704 A .2.5 except as modified in this section . Special inspections of site-built assemblies shall be in accordance with this section.

    1705 A .5.1 High-load diaphragms. High-load diaphragms designed in accordance with Section 2306.2 or 2307.1 shall be installed with special inspections as indicated in Section 1704 A .2. The special inspector shall inspect the wood structural panel sheathing to ascertain whether it is of the grade and thickness shown on the approved construction documents. Additionally, the special inspector must verify the nominal size of framing members at adjoining panel edges, the nail or staple diameter and length, the number of fastener lines and that the spacing between fasteners in each line and at edge margins agrees with the approved construction documents.

    1705 A .5.2 Metal-plate-connected wood trusses spanning 60 feet or greater. Where a truss clear span is 60 feet (18 288 mm) or greater, the special inspector shall verify that the temporary installation restraint/bracing and the permanent individual truss member restraint/bracing are installed in accordance with the approved truss submittal package.

    1705 A .5.3 Mass timber construction. Special inspections of mass timber elements in Types IV-A, IV-B and IV-C construction shall be in accordance with Table 1705 A .5.3.

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    TABLE 1705A.5.3—REQUIRED SPECIAL INSPECTIONS OF MASS TIMBER CONSTRUCTION Col2 Col3 Col4
    TYPE TYPE CONTINUOUS
    SPECIAL
    INSPECTION    		 PERIODIC
    SPECIAL
    INSPECTION
    1. Inspection of anchorage and connections of mass timber construction to timber deep foundation
    systems.    		 — X
    2. Inspect erection of mass timber construction. — X
    3. Inspection of connections where installation methods are required to meet design loads.
    _3.1.
  • CBC § 1705.5.2 High relevance — show source text

    1705.5.2 Metal-plate-connected wood trusses spanning 60 feet or greater. Where a truss clear span is 60 feet (18 288 mm) or greater, the special inspector shall verify that the temporary installation restraint/bracing and the permanent individual truss member restraint/bracing are installed in accordance with the approved truss submittal package.

    1705.5.3 Mass timber construction. Special inspections of mass timber elements in Types IV-A, IV-B and IV-C construction shall be in accordance with Table 1705.5.3.

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    TABLE 1705.5.3—REQUIRED SPECIAL INSPECTIONS OF MASS TIMBER CONSTRUCTION Col2 Col3 Col4 Col5
    TYPE TYPE TYPE CONTINUOUS
    SPECIAL INSPECTION    		 PERIODIC SPECIAL
    INSPECTION
    1. Inspection of anchorage and connections of mass timber construction to timber deep
    foundation systems.    		 Inspection of anchorage and connections of mass timber construction to timber deep
    foundation systems.    		 — X
    2. Inspect erection of mass timber construction. Inspect erection of mass timber construction. — X
    3. Inspection of connections where installation methods are required to meet design loads. Inspection of connections where installation methods are required to meet design loads.
    Threaded fasteners. Verify use of proper installation equipment. — X
    Threaded fasteners. Verify use of pre-drilled holes where required. — X
    Threaded fasteners. Inspect screws, including diameter, length, head type, spacing,
    installation angle and depth.    		 — X
    Adhesive anchors installed in horizontal or upwardly inclined orientation to resist
    sustained tension loads.    		 Adhesive anchors installed in horizontal or upwardly inclined orientation to resist
    sustained tension loads.    		 X —
    Adhesive anchors not defined in preceding cell. Adhesive anchors not defined in preceding cell. — X
    Bolted connections. Bolted connections. — X
    Concealed connections. Concealed connections. — X

    1705.5.4 Manufactured trusses and assemblies. [OSHPD 1R, 2 & 5] The fabrication of trusses and other assemblages constructed using wood and metal members, or using light metal plate connectors, shall be continuously inspected by an approved agency. The approved agency shall furnish the architect, structural engineer and the enforcement agency with a report that the lumber species, grades and moisture content; type of glue, temperature and gluing procedure; type of metal members and metal plate connectors; and the workmanship conform in every material respect with the duly approved construction documents. Each inspected truss shall be stamped by the approved agency with an identifying mark.

    1705.5.5 Structural glued laminated and cross-laminated timber. [OSHPD 1R, 2 & 5] Manufacture of all structural glued lami- nated and cross-laminated timber shall be continuously inspected by an approved agency.

  • CBC § 1705.4.1 High relevance — show source text

    1705.4.1 Glass unit masonry and masonry veneer in Risk Category IV. Special inspections and tests for glass unit masonry or masonry veneer designed in accordance with Section 2110 or Chapter 14, respectively, where they are part of a structure classified as Risk Category IV shall be performed in accordance with TMS 602 Level 2. [OSHPD 1R, 2 & 5] Not permitted by OSHPD.

    [OSHPD 1R, 2 & 5] Glass unit masonry and masonry veneer in Risk Category II, III or IV. Special inspections and tests for glass unit masonry or masonry veneer designed by Section 2110 or Chapter 14, respectively, in structures classified as Risk Category II, III or IV, shall be performed in accordance with TMS 602 Tables 3 and 4, Level 2 Quality Assurance.

    1705.4.1.1 TMS 602 Section 1.6 Quality Assurance. [OSHPD 1R, 2 & 5] Replace footnote (d) as follows: (d) Periodic special inspection is required for all veneer.

    1705.4.2 Vertical masonry foundation elements. Special inspections and tests of vertical masonry foundation elements shall be performed in accordance with Section 1705.4.

    1705.5 Wood construction. Special inspections of prefabricated wood structural elements and assemblies shall be in accordance with Section 1704.2.5. Special inspections of site-built assemblies shall be in accordance with this section.

    1705.5.1 High-load diaphragms. High-load diaphragms designed in accordance with Section 2306.2 shall be installed with special inspections as indicated in Section 1704.2. The special inspector shall inspect the wood structural panel sheathing to ascertain whether it is of the grade and thickness shown on the approved construction documents. Additionally, the special inspector must verify the nominal size of framing members at adjoining panel edges, the nail or staple diameter and length, the number of fastener lines and that the spacing between fasteners in each line and at edge margins agrees with the approved construction documents.

    1705.5.2 Metal-plate-connected wood trusses spanning 60 feet or greater. Where a truss clear span is 60 feet (18 288 mm) or greater, the special inspector shall verify that the temporary installation restraint/bracing and the permanent individual truss member restraint/bracing are installed in accordance with the approved truss submittal package.

    1705.5.3 Mass timber construction. Special inspections of mass timber elements in Types IV-A, IV-B and IV-C construction shall be in accordance with Table 1705.5.3.

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    TABLE 1705.5.3—REQUIRED SPECIAL INSPECTIONS OF MASS TIMBER CONSTRUCTION Col2 Col3 Col4 Col5
    TYPE TYPE TYPE CONTINUOUS
    SPECIAL INSPECTION    		 PERIODIC SPECIAL
    INSPECTION
    1. Inspection of anchorage and connections of mass timber construction to timber deep
    foundation systems.
  • CBC § 5.2 High relevance — show source text

    1705 A .5.2 Metal-plate-connected wood trusses spanning 60 feet or greater. Where a truss clear span is 60 feet (18 288 mm) or greater, the special inspector shall verify that the temporary installation restraint/bracing and the permanent individual truss member restraint/bracing are installed in accordance with the approved truss submittal package.

    1705 A .5.3 Mass timber construction. Special inspections of mass timber elements in Types IV-A, IV-B and IV-C construction shall be in accordance with Table 1705 A .5.3.

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    TABLE 1705A.5.3—REQUIRED SPECIAL INSPECTIONS OF MASS TIMBER CONSTRUCTION Col2 Col3 Col4
    TYPE TYPE CONTINUOUS
    SPECIAL
    INSPECTION    		 PERIODIC
    SPECIAL
    INSPECTION
    1. Inspection of anchorage and connections of mass timber construction to timber deep foundation
    systems.    		 — X
    2. Inspect erection of mass timber construction. — X
    3. Inspection of connections where installation methods are required to meet design loads.
    _3.1._Threaded fasteners. — X
    _ 3.1.1._ Verify use of proper installation equipment. — X
    _ 3.1.2._ Verify use of pre-drilled holes where required. — X
    _ 3.1.3._ Inspect screws, including diameter, length, head type, spacing, installation angle and depth.
    _3.2._Adhesive anchors installed in horizontal or upwardly inclined orientation to resist sustained
    tension loads.    		 X —
    _3.3._Adhesive anchors not defined in preceding cell. — X
    _3.4._Bolted connections. — X
    3.5.Concealed connections.([DSA-SS, DSA-SS/CC]See Sec. 110.3.5 for wood-covered connections.) — X

    1705A.5.4 Wood structural elements and assemblies. Special inspection of wood structural elements and assemblies is required, as specified in this section, to ensure conformance with approved construction documents and applicable standards.

    The approved agency shall furnish a verified report to the design professional in general responsible charge of construction obser- vation, the structural engineer and the enforcement agency, in accordance with the California Administrative Code and this chapter. The verified report shall list all inspected members or trusses, and shall indicate whether or not the inspected members or trusses conform with applicable standards and the approved drawings and specifications. Any nonconforming items shall be indicated on the verified report.

    1705A.5.5 Structural glued laminated and cross-laminated timber. Manufacture of all structural glued laminated and cross-lami- nated timber shall be continuously inspected by an approved agency.

  • CBC § 18.1 High relevance — show source text

    [DSA SS, DSA-SS/CC] Buildings assigned to Risk Category II, III or IV shall be subject to special inspections for fire-resistant penetrations and joints.

    [BF] 1705 A .18.1 Penetration firestops. Inspections of penetration firestop systems that are tested and listed in accordance with Sections 714.4.1.2 and 714.5.1.2 shall be conducted by an approved agency in accordance with ASTM E2174.

    [BF] 1705 A .18.2 Fire-resistant joint systems. Inspection of fire-resistant joint systems that are tested and listed in accordance with Sections 715.3.1 and 715.4 shall be conducted by an approved agency in accordance with ASTM E2393.

    [F] 1705 A .19 Testing for smoke control. Smoke control systems shall be tested by a special inspector.

    [F] 1705 A .19.1 Testing scope. The test scope shall be as follows:

    1. During erection of ductwork and prior to concealment for the purposes of leakage testing and recording of device location.

    2. Prior to occupancy and after sufficient completion for the purposes of pressure difference testing, flow measurements and detection and control verification.

    [F] 1705 A .19.2 Qualifications. Approved agencies for smoke control testing shall have expertise in fire protection engineering, mechanical engineering and certification as air balancers.

    1705 A .20 Sealing of mass timber. Periodic special inspections of sealants or adhesives shall be conducted where sealant or adhesive required by Section 703.7 is applied to mass timber building elements as designated in the approved construction documents.

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    SECTION 1706 A —DESIGN STRENGTHS OF MATERIALS

    1706 A .1 Conformance to standards. The design strengths and permissible stresses of any structural material that are identified by a manufacturer’s designation as to manufacture and grade by mill tests, or the strength and stress grade is otherwise confirmed to the satisfaction of the building official, shall conform to the specifications and methods of design of accepted engineering practice or the approved rules in the absence of applicable standards.

    1706 A .2 New materials. For materials that are not specifically provided for in this code, the design strengths and permissible stresses shall be established by tests as provided for in Section 1707 A .

    SECTION 1707 A —ALTERNATIVE TEST PROCEDURE

    1707 A .1 General. In the absence of approved rules or other approved standards, the building official shall make, or cause to be made, the necessary tests and investigations; or the building official shall accept duly authenticated reports from approved agencies in respect to the quality and manner of use of new materials or assemblies as provided for in Section 104.2.3. The cost of all tests and other investigations required under the provisions of this code shall be borne by the owner or the owner’s authorized agent.

    SECTION 1708 A —IN-SITU LOAD TESTS

    1708 A **.1 General.

  • CBC § 3.1.1. High relevance — show source text

    |—|X| ||_ 3.1.1._ Verify use of proper installation equipment.|—|X| ||_ 3.1.2._ Verify use of pre-drilled holes where required.|—|X| ||_ 3.1.3._ Inspect screws, including diameter, length, head type, spacing, installation angle and depth.||| ||_3.2._Adhesive anchors installed in horizontal or upwardly inclined orientation to resist sustained
    tension loads.|X|—| ||_3.3._Adhesive anchors not defined in preceding cell.|—|X| ||3.4.Bolted connections.|—|X| ||3.5.Concealed connections.(**[DSA-SS, DSA-SS/CC]**See Sec. 110.3.5 for wood-covered connections.)|—|X|

    1705A.5.4 Wood structural elements and assemblies. Special inspection of wood structural elements and assemblies is required, as specified in this section, to ensure conformance with approved construction documents and applicable standards.

    The approved agency shall furnish a verified report to the design professional in general responsible charge of construction obser- vation, the structural engineer and the enforcement agency, in accordance with the California Administrative Code and this chapter. The verified report shall list all inspected members or trusses, and shall indicate whether or not the inspected members or trusses conform with applicable standards and the approved drawings and specifications. Any nonconforming items shall be indicated on the verified report.

    1705A.5.5 Structural glued laminated and cross-laminated timber. Manufacture of all structural glued laminated and cross-lami- nated timber shall be continuously inspected by an approved agency.

    The approved agency shall verify that proper quality control procedures and tests have been employed for all materials and the manufacturing process, and shall perform visual inspection of the finished product. Each inspected member shall be stamped by the approved agency with an identification mark.

    Exception: Special Inspection is not required for non-custom prismatic glued laminated members identified on drawings and sourced from stock or general inventory of 5 [1] / 2 -inch maximum width and 18-inch maximum depth, and with a maximum clear span of 32 feet, manufactured and marked in accordance with ANSI/APA A190.1 Section 14.1 for noncustom members.

    1705A.5.6 Manufactured open web trusses. The manufacture of open web trusses shall be continuously inspected by an approved

    agency.

    The approved agency shall verify that proper quality control procedures and tests have been employed for all materials and the manufacturing process, and shall perform visual inspection of the finished product. Each inspected truss shall be stamped with an identification mark by the approved agency.

    1705A.5.7 Timber connectors. The installation of all split ring and shear plate timber connectors, and timber rivets shall be continuously inspected by an approved agency. The approved agency shall furnish the architect, structural engineer and the enforcement agency with a report verifying that the materials, timber connectors and workmanship conform to the approved construction documents.

    1705 A .6 Soils. Special inspections and tests of existing site soil conditions, fill placement and load-bearing requirements shall be performed in accordance with this section and Table 1705 A .6. The approved geotechnical report and the construction documents prepared by the registered design professionals shall be used to determine compliance.

  • CBC § 1705.18.1 High relevance — show source text

    [OSHPD 1R, 2 & 5] Buildings assigned to all Risk Categories shall be subject to special inspections for fire-resistant penetrations and joints.

    [BF] 1705.18.1 Penetration firestops. Inspections of penetration firestop systems that are tested and listed in accordance with Sections 714.4.1.2 and 714.5.1.2 shall be conducted by an approved agency in accordance with ASTM E2174.

    [BF] 1705.18.2 Fire-resistant joint systems. Inspection of fire-resistant joint systems that are tested and listed in accordance with Sections 715.3.1 and 715.4 shall be conducted by an approved agency in accordance with ASTM E2393.

    [F] 1705.19 Testing for smoke control. Smoke control systems shall be tested by a special inspector.

    [F] 1705.19.1 Testing scope. The test scope shall be as follows:

    1. During erection of ductwork and prior to concealment for the purposes of leakage testing and recording of device location.

    2. Prior to occupancy and after sufficient completion for the purposes of pressure difference testing, flow measurements and detection and control verification.

    [F] 1705.19.2 Qualifications. Approved agencies for smoke control testing shall have expertise in fire protection engineering, mechanical engineering and certification as air balancers.

    1705.20 Sealing of mass timber. Periodic special inspections of sealants or adhesives shall be conducted where sealant or adhesive required by Section 703.7 is applied to mass timber building elements as designated in the approved construction documents.

    SECTION 1706—DESIGN STRENGTHS OF MATERIALS

    1706.1 Conformance to standards. The design strengths and permissible stresses of any structural material that are identified by a manufacturer’s designation as to manufacture and grade by mill tests, or the strength and stress grade is otherwise confirmed to the satisfaction of the building official, shall conform to the specifications and methods of design of accepted engineering practice or the approved rules in the absence of applicable standards.

    1706.2 New materials. For materials that are not specifically provided for in this code, the design strengths and permissible stresses shall be established by tests as provided for in Section 1707.

    SECTION 1707—ALTERNATIVE TEST PROCEDURE

    1707.1 General. In the absence of approved rules or other approved standards, the building official shall make, or cause to be made, the necessary tests and investigations; or the building official shall accept duly authenticated reports from approved agencies in respect to the quality and manner of use of new materials or assemblies as provided for in Section 104.2.3 or 1.8.7, as applicable. The cost of all tests and other investigations required under the provisions of this code shall be borne by the owner or the owner’s authorized agent.

    [BSC] In the absence of approved rules or other approved standards, the building official shall make, or cause to be made, the neces- sary tests and investigations; or the building official shall accept duly authenticated reports from approved agencies in respect to the quality and manner of use of new materials or assemblies as provided for in Section 1.2.1, Chapter 1, Division I. The cost of all tests and other investigations required under the provisions of this code shall be borne by the applicant.

    SECTION 1708—IN-SITU LOAD TESTS

    **1708.1 General.

  • CBC § 14.1 High relevance — show source text

    The approved agency shall verify that proper quality control procedures and tests have been employed for all materials and the manufacturing process, and shall perform visual inspection of the finished product. Each inspected member shall be stamped by the approved agency with an identification mark.

    Exception: Special Inspection is not required for non-custom prismatic glued laminated members identified on drawings and sourced from stock or general inventory of 5 [1] / 2 -inch maximum width and 18-inch maximum depth, and with a maximum clear span of 32 feet, manufactured and marked in accordance with ANSI/APA A190.1 Section 14.1 for noncustom members.

    1705A.5.6 Manufactured open web trusses. The manufacture of open web trusses shall be continuously inspected by an approved

    agency.

    The approved agency shall verify that proper quality control procedures and tests have been employed for all materials and the manufacturing process, and shall perform visual inspection of the finished product. Each inspected truss shall be stamped with an identification mark by the approved agency.

    1705A.5.7 Timber connectors. The installation of all split ring and shear plate timber connectors, and timber rivets shall be continuously inspected by an approved agency. The approved agency shall furnish the architect, structural engineer and the enforcement agency with a report verifying that the materials, timber connectors and workmanship conform to the approved construction documents.

    1705 A .6 Soils. Special inspections and tests of existing site soil conditions, fill placement and load-bearing requirements shall be performed in accordance with this section and Table 1705 A .6. The approved geotechnical report and the construction documents prepared by the registered design professionals shall be used to determine compliance.

    Exception: Where Section 1803 does not require reporting of materials and procedures for fill placement, the special inspector shall verify that the in-place dry density of the compacted fill is not less than 90 percent of the maximum dry density at optimum moisture content determined in accordance with ASTM D1557.

    [DSA-SS, DSA-SS/CC] Additional exceptions to soils special inspections and tests are permitted for the following cases when all the following occur: A) no geotechnical report is required; B) the design is permitted to be and is based on Section 1806A.2 and Table 1806A.2; C) cases are identified on the approved construction documents. 1. Deep foundations for the following structures: a. Freestanding sign or scoreboard. b. Telecommunications towers and poles less than 35 feet 0 inches above lowest adjacent grade. c. Poles less than 35 feet 0 inches above lowest adjacent grade for lighting, flags, open mesh fences and similar structures.

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    SPECIAL INSPECTIONS AND TESTS

    d. Single-story structure with dead load less than 5 psf. e. Covered walkway structure with an apex height less than 10 feet 0 inches above lowest adjacent grade.

    2. Shallow foundations or excavations for:

  • CBC § 2.5 High relevance — show source text

    All reports shall describe the nature and extent of inspections and tests, the location where the inspections and tests were performed, and indicate that work inspected or tested was or was not completed in conformance to approved construction documents . Discrepancies shall be brought to the immediate attention of the contractor for correction. If they are not corrected, the discrepancies shall be brought to the attention of the building official and to the registered design professional in responsible charge prior to the completion of that phase of the work. A final report documenting required special inspections and tests, and correction of any discrepancies noted in the inspections or tests, shall be submitted at a point in time agreed upon prior to the start of work by the owner or the owner’s authorized agent to the building official.

    1704 A .2.5 Special inspection of fabricated items. Where fabrication of structural, load-bearing or lateral load-resisting members or assemblies is being conducted on the premises of a fabricator’s shop, special inspections of the fabricated items shall be performed during fabrication.

    1704 A .2.5.1 Fabricator approval. Not permitted by DSA-SS, DSA-SS/CC or OSHPD.

    1704 A .3 Statement of special inspections. Where special inspections or tests are required by Section 1705 A, the registered design professional in responsible charge shall prepare a statement of special inspections in accordance with Section 1704 A .3.1 for submittal by the applicant in accordance with Section 1704 A .2.3.

    Exception: The statement of special inspections is permitted to be prepared by a qualified person approved by the building official for construction not designed by a registered design professional.

    [DSA-SS, DSA-SS/CC] The exception is not permitted by DSA.

    1704 A .3.1 Content of statement of special inspections. The statement of special inspections shall identify the following:

    1. The materials, systems, components and work required to have special inspections or tests by the building official or by the registered design professional responsible for each portion of the work.

    2. The type and extent of each special inspection.

    3. The type and extent of each test.

    4. Additional requirements for special inspections or tests for seismic or wind resistance as specified in Sections 1705 A .12, 1705 A .13 and 1705 A .14.

    5. For each type of special inspection, identification as to whether it will be continuous special inspection, periodic special inspection or performed in accordance with the notation used in the referenced standard where the inspections are defined.

    6. Deferred submittal items that require a supplemental statement of special inspections.

    1704 A .3.2 Seismic requirements in the statement of special inspections. Where Section 1705 A .13 or 1705 A .14 specifies special inspections or tests for seismic resistance, the statement of special inspections shall identify the equipment/components that require special seismic certification and seismic force-resisting systems that are subject to the special inspections or tests.

    1704 A .3.3 Wind requirements in the statement of special inspections. Where Section 1705 A .12 specifies special inspection for wind resistance, the statement of special inspections shall identify the main windforce-resisting systems and wind-resisting components that are subject to special inspections.

    2025 CALIFORNIA BUILDING CODE 17A-5

  • CBC § 1704.2.2 Medium relevance — show source text

    The registered design professional in responsible charge and engineers of record involved in the design of the project are permitted to act as an approved agency and their personnel are permitted to act as special inspectors for the work designed by them, provided they qualify as special inspectors.

    1704.2.2 Access for special inspection. The construction or work for which special inspection or testing is required shall remain accessible and exposed for special inspection or testing purposes until completion of the required special inspections or tests.

    1704.2.3 Statement of special inspections. The applicant shall submit a statement of special inspections in accordance with Section 107.1 as a condition for permit issuance. This statement shall be in accordance with Section 1704.3.

    Exception: A statement of special inspections is not required for portions of structures designed and constructed in accordance with the cold-formed steel light-frame construction provisions of Section 2206.1.2 or the conventional light-frame construction provisions of Section 2308. [OSHPD 1R, 2 & 5] Not permitted by OSHPD.

    1704.2.4 Report requirement. Approved agencies shall keep records of special inspections and tests. The approved agency shall submit reports of special inspections and tests to the building official and to the registered design professional in responsible charge at frequencies required by the approved construction documents or building official. All reports shall describe the nature and extent of inspections and tests, the location where the inspections and tests were performed, and indicate that work inspected or tested was or was not completed in conformance to approved construction documents. Discrepancies shall be brought to the immediate attention of the contractor for correction. If they are not corrected, the discrepancies shall be brought to the attention of the building official and to the registered design professional in responsible charge prior to the completion of that phase of the work. A final report documenting required special inspections and tests, and correction of any discrepancies noted in the inspections or tests, shall be submitted at a point in time agreed upon prior to the start of work by the owner or the owner’s authorized agent to the building official. [OSHPD 1R, 2 & 5] Report requirement shall be per 1704A.2.4.

    1704.2.5 Special inspection of fabricated items. Where fabrication of structural, load-bearing or lateral load-resisting members or assemblies is being conducted on the premises of a fabricator’s shop, special inspections of the fabricated items shall be performed during fabrication, except where the fabricator has been approved to perform work without special inspections in accordance with Section 1704.2.5.1.

    1704.2.5.1 Fabricator approval. [OSHPD 1R, 2 & 5] Not permitted by OSHPD. Special inspections during fabrication are not required where the work is done on the premises of a fabricator approved to perform such work without special inspection. Approval shall be based on review of the fabricator’s written fabrication procedures and quality control manuals that provide a basis for control of materials and workmanship, with periodic auditing of fabrication and quality control practices by an approved agency or the building official. At completion of fabrication, the approved fabricator shall submit a certificate of compliance to the owner or the owner’s authorized agent for submittal to the building official as specified in Section 1704.5 stating that the work was performed in accordance with the approved construction documents.

  • CBC § 1404.2 Medium relevance — show source text

    Weather Protection

    Exterior walls 1404.2

    Roofs 1503 Welding Materials, verification of steel reinforcement 1705.3.2 Special inspections 1705.13.3, 1705.2, 1705.3.1 Splices of reinforcement in masonry 2107.3, 2108.3 Wildland-Urban Interface 101.4.8

    Wind Load 1609 Basic design wind speed 1609.3 Construction documents

    107, 1603.1.4 Exposure category 1609.4 Glazing 1609.2, 2404 Hurricane 1507.1.1 Masonry, empirical design 2109.1.1 Nominal design wind speed 1609.3.1 Roofs 1504.1, 1609.6, 2308.11.4 Seismic detailing required 1604.10 Special inspection 1705.12 Statement of special inspections 1704.3 Wind design geodatabase 1609.3 Wind tunnel testing 1504.3.1.2, 1609.1.1 Winders, stair (see Stairway Construction) Window Accessibility 11B-229 Emergency egress 1031 Exterior, structural testing 1709.5 Fire (see Opening Protectives) 716.2, 716.2.8 Glass (see Glazing) 1404.14 Guards 1015.8 Required light 1204.1, 1204.2 Wells 1031.6 Wires, Penetration Protection 714 Wood Chapter 23 Allowable stress design 2306 Bracing, walls 2308.10 Calculated fire resistance 722.6 Ceiling framing 2308.11 Connectors and fasteners 2304.10,

    2308.5

    Contacting concrete, masonry or earth 2304.12.1.3, 2304.12.1.4, 2304.12.2.1, 2304.12.2.2, 2304.12.2.6 Cross-laminated timber 2301.2, 2303.1, 2303.1.4, 2304.11.2.1, 2304.11.3.1, 2304.11.4.1 Cutting, notching and boring of dimensional wood framing 2308.6 Decay, protection against 2304.12 Diaphragms 2305.1, 2305.2, 2306.2 Dimensions 2301.2 Draftstopping 718.3, 718.4 End-jointed lumber 2303.1.1.2 Fiberboard 2303.1.6, Table 2306.3(2) Fireblocking 718.2 Fire-retardant treated 2303.2 Floor and roof framing (see Floor Construction, Wood) 2304.4 Floor sheathing 2304.8 Foundation 1807.1.4, 2304.10.6.2, 2304.12.1.2, 2308.10.8.1, 2308.7 Grade, lumber 2303.1.1

    INDEX-22 2025 CALIFORNIA BUILDING CODE

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

  • CBC § 1704A.2.4. Medium relevance — show source text

    If they are not corrected, the discrepancies shall be brought to the attention of the building official and to the registered design professional in responsible charge prior to the completion of that phase of the work. A final report documenting required special inspections and tests, and correction of any discrepancies noted in the inspections or tests, shall be submitted at a point in time agreed upon prior to the start of work by the owner or the owner’s authorized agent to the building official. [OSHPD 1R, 2 & 5] Report requirement shall be per 1704A.2.4.

    1704.2.5 Special inspection of fabricated items. Where fabrication of structural, load-bearing or lateral load-resisting members or assemblies is being conducted on the premises of a fabricator’s shop, special inspections of the fabricated items shall be performed during fabrication, except where the fabricator has been approved to perform work without special inspections in accordance with Section 1704.2.5.1.

    1704.2.5.1 Fabricator approval. [OSHPD 1R, 2 & 5] Not permitted by OSHPD. Special inspections during fabrication are not required where the work is done on the premises of a fabricator approved to perform such work without special inspection. Approval shall be based on review of the fabricator’s written fabrication procedures and quality control manuals that provide a basis for control of materials and workmanship, with periodic auditing of fabrication and quality control practices by an approved agency or the building official. At completion of fabrication, the approved fabricator shall submit a certificate of compliance to the owner or the owner’s authorized agent for submittal to the building official as specified in Section 1704.5 stating that the work was performed in accordance with the approved construction documents.

    1704.3 Statement of special inspections. Where special inspections or tests are required by Section 1705, the registered design professional in responsible charge shall prepare a statement of special inspections in accordance with Section 1704.3.1 for submittal by the applicant in accordance with Section 1704.2.3.

    Exception: The statement of special inspections is permitted to be prepared by a qualified person approved by the building official for construction not designed by a registered design professional.

    1704.3.1 Content of statement of special inspections. The statement of special inspections shall identify the following:

    1. The materials, systems, components and work required to have special inspections or tests by the building official or by the registered design professional responsible for each portion of the work.

    2. The type and extent of each special inspection.

    3. The type and extent of each test.

    4. Additional requirements for special inspections or tests for seismic or wind resistance as specified in Sections 1705.12, 1705.13 and 1705.14.

    5. For each type of special inspection, identification as to whether it will be continuous special inspection, periodic special inspection or performed in accordance with the notation used in the referenced standard where the inspections are defined.

    6. Deferred submittal items that require a supplemental statement of special inspections.

    2025 CALIFORNIA BUILDING CODE 17-5

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

    SPECIAL INSPECTIONS AND TESTS

Frequently asked questions

Do all wood buildings require special inspections?

No. Only those wood elements and operations specifically listed in § 1705.5 (and associated tables/ subsections) and the mass timber tables require special inspections; prefabricated items follow the fabrication inspection rules in § 1704.2.5.

When is inspection continuous vs periodic for mass timber anchors?

Table 1705.5.3 / 1705A.5.3 identifies adhesive anchors installed in a horizontal or upwardly inclined orientation to resist sustained tension as requiring continuous inspection; many other anchors and connections are periodic. Check the table entries for each anchor/connection type.

Are factory/manufacturer inspections required?

Yes — the manufacture of trusses and of structural glued‑laminated and cross‑laminated timber is required to be continuously inspected by an approved agency; the approved agency must provide verified reports and identification marks.

What if a glulam member is stock and non‑custom?

There is a specific exception for non‑custom prismatic glued‑laminated members meeting size/span and marking criteria (ANSI/APA A190.1) — those may be exempt from special manufacture inspection; review the exception text carefully.

Who prepares the statement of special inspections?

The registered design professional in responsible charge prepares the statement of special inspections (unless the code exception permits an approved qualified person); the statement is a required permit submittal per § 1704.

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