What Is Special Inspection? A Guide to CBC and IBC Chapter 17

Special inspection is independent inspection of specific structural and fire-resistive work by a qualified special inspector from an approved agency. Section 1705 of the 2024 International Building Code (IBC) and the 2025 California Building Code (CBC) lists the work, the owner hires the agency, and it is in addition to the building department's own inspections.

If you are an owner or first-time developer asking what is special inspection and why it appears on your permit, this guide gives the short answer from the code text, then the detail: who hires whom, which work is covered, how continuous and periodic inspection differ, and how to plan for it.

What is special inspection in construction?

Special inspection is inspection of construction that needs a qualified special inspector to confirm it complies with the building code and the approved construction documents. The 2024 IBC defines the term in Section 202, and Section 202 of the 2025 CBC uses the same wording.

The definition begins:

"Inspection of construction requiring the expertise of an approved special inspector" (2024 IBC Section 202, definition of SPECIAL INSPECTION; the same wording appears in the 2025 CBC)

The rest of the definition states the purpose: to make sure the work complies with the code and with the approved construction documents. Two related definitions in Section 202 matter to owners. A special inspector is a qualified person employed or retained by an approved agency and approved by the building official as competent to inspect a particular type of construction. An approved agency is an established organization regularly engaged in testing, inspection or product evaluation that the building official has approved. You can read both in the 2024 IBC Chapter 2 definitions.

Older drafts and some web pages place these definitions in Section 1702. In the 2024 IBC, Section 1702 is "New Materials", and the definitions sit in Section 202. Cite Section 202 when you quote the definition from the current edition.

In the City of Los Angeles and many nearby jurisdictions, the person doing this work is often called a deputy inspector. The term comes from the Los Angeles Department of Building and Safety (LADBS), which certifies its own inspectors for this role, so check the jurisdiction's rules on which credentials it accepts before you hire.

Why does the building code require special inspection?

The code requires special inspection because some work cannot be judged in a short visit by a building inspector, and much of it is hidden once the next trade covers it. Welds, bolt tightening, rebar placement, concrete sampling and compacted fill all need a specialist at the right moment.

The user note to Chapter 17 of the 2024 IBC explains that the chapter expands on the inspections in Chapter 1 by requiring special inspection by a qualified individual where indicated, and structural observation by a registered design professional in some cases. Compliance often depends on inspection and testing at specific stages of construction, which a general site visit cannot catch.

The code also builds in independence. Section 1703.1.1 requires an approved agency to be objective, competent and independent from the contractor whose work it inspects, and to disclose possible conflicts of interest to the building official and the registered design professional in responsible charge. That independence is the reason the owner, not the contractor, hires the agency.

Special inspection also produces a record. Under Section 1704.2.4, the agency keeps records, sends reports to the building official and the registered design professional, and states whether the inspected work was or was not completed in conformance with the approved construction documents. A final report documents the required inspections and the correction of any discrepancies.

Who hires the special inspection agency?

The owner or the owner's authorized agent hires the special inspection agency, and the contractor may not, unless the contractor is also the owner. This is the rule most often misstated in drafts and bid documents.

Section 1704.2 of both the 2024 IBC and the 2025 CBC requires the owner or the owner's authorized agent, other than the contractor, to employ one or more approved agencies for the special inspections and tests listed in Section 1705, and to identify those agencies to the building official. The same section states that these inspections are in addition to the building official's inspections under Section 110. The CBC version adds a reference to Section 1.8.4 alongside Section 105 for the permit application. Read the full text in 2025 CBC Chapter 17. The 2025 CBC took effect statewide on January 1, 2026, according to the California Building Standards Commission; check which edition applies to your permit application date.

Section 1704.2 lists four exceptions:

1. Construction of a minor nature, or as warranted by conditions in the jurisdiction, where the building official approves.
2. Group U occupancies accessory to a residential occupancy, unless the building official requires inspection.
3. Portions of structures built under the cold-formed steel light-frame provisions of Section 2206.1.2 or the conventional light-frame provisions of Section 2308.
4. The contractor may employ the agency where the contractor is also the owner.

Each party on a permitted project has a defined role in Chapter 17:

The engineer of record can also act as the approved agency. Section 1704.2.1 permits the registered design professional in responsible charge and the engineers of record to act as an approved agency for work they designed, provided their personnel qualify as special inspectors.

How is special inspection different from building inspection and structural observation?

Special inspection, building inspection and structural observation are three separate activities with different people, scopes and code sections. One never replaces another.

Building inspection is done by the building department's own inspectors under Section 110. It covers the permit inspections every project receives, such as footings, framing and final.

Special inspection is done by a special inspector from an approved agency the owner hires, on the work types listed in Section 1705. It is detailed, task-by-task verification, sometimes with the inspector present full time.

Structural observation is done by a registered design professional, usually the structural engineer. Section 202 defines it as visual observation of the structural system for general conformance to the approved construction documents. Section 1704.6 says the observer looks at representative locations of structural systems, details and load paths, and that structural observation does not include or waive the inspections in Section 110 or the special inspections in Section 1705.

Under Section 1704.6.1, structural observation is required where any of the following applies:

• the structure is Risk Category III or IV
• the structure is a high-rise building
• the structure is in Seismic Design Category E and is more than two stories above grade plane
• the registered design professional responsible for the structural design requires it
• the building official specifically requires it

What work needs special inspection?

The work types are listed in Section 1705 of the 2024 IBC and the 2025 CBC, and the project's statement of special inspections says which apply to your building. Many items have exceptions, so the list below is a starting map, not a checklist for every job.

Section 1705.1.1 adds a catch-all. The building official may require special inspection for unusual work, such as alternative materials, unusual design applications, or systems installed to manufacturer's instructions that go beyond the code.

The concrete exceptions in Section 1705.3 matter to many owners. Special inspection is not required for isolated spread footings of buildings three stories or less above grade plane that are fully supported on earth or rock, for nonstructural slabs on grade, or for patios, driveways and sidewalks on grade. Continuous wall footings are exempt only when they support light-frame walls, follow Table 1809.7 and are designed for a specified compressive strength of no more than 2,500 psi.

California adds its own provisions. The 2025 CBC Chapter 17 includes amendments, marked [OSHPD], for certain health facilities, such as continuous batch plant inspection in Section 1705.3.3 and a structural welding section, 1705.2.7, that sets the AWS Certified Welding Inspector as the minimum qualification. Public schools, community colleges, state essential services buildings and hospitals follow a separate chapter, CBC Chapter 17A, under the Division of the State Architect and the Department of Health Care Access and Information.

For a closer look at single disciplines, see the guides to concrete and reinforcing steel inspection, structural steel inspection and SFRM fireproofing inspection.

What is the difference between continuous and periodic special inspection?

Continuous special inspection means the special inspector is present the whole time the work is being performed. Periodic special inspection means the inspector is present intermittently, where the work has been or is being performed. Both terms are defined in Section 202 under SPECIAL INSPECTION. The 2025 CBC adds, for buildings under DSA and OSHPD jurisdiction, that periodic inspection also takes place at the completion of the work.

The frequency is set task by task in the code tables, not by the inspector or the contractor. Table 1705.3 for concrete shows how one material can carry both:

• Periodic: inspecting reinforcement and verifying its placement; inspecting anchors cast in concrete; verifying use of the required design mix; verifying curing temperature and techniques; inspecting formwork.
• Continuous: fabricating strength-test specimens and performing slump, air content and temperature tests before placement; inspecting concrete and shotcrete placement; inspecting adhesive anchors installed horizontally or upwardly inclined to resist sustained tension loads.

Table 1705.6 for soils works the same way. Verifying fill materials, lift thicknesses and densities during placement and compaction is continuous; checking excavation depth and subgrade preparation is periodic.

Some referenced standards use their own notation. Section 1704.3.1 lets the statement of special inspections mark a task as continuous, periodic, or "performed in accordance with the notation used in the referenced standard." Structural steel is the common case: the AISC 360 quality assurance tables assign each welding and bolting task as "observe" or "perform" rather than continuous or periodic.

Continuous inspection costs more inspector hours, so the frequency is the first thing to read when you budget. The special inspection services page explains how scope and frequency are agreed.

What does the statement of special inspections contain?

The statement of special inspections is the project's list of required inspections and tests. Under Section 1704.3, the registered design professional in responsible charge prepares it, and under Section 1704.2.3 the applicant submits it as a condition of permit issuance.

Section 1704.3.1 requires the statement to identify:

1. the materials, systems, components and work that need special inspection or testing
2. the type and extent of each special inspection
3. the type and extent of each test
4. additional requirements for seismic or wind resistance under Sections 1705.12, 1705.13 and 1705.14
5. whether each inspection is continuous, periodic or per the referenced standard's notation
6. deferred submittal items that need a supplemental statement

Where seismic or wind inspections apply, Sections 1704.3.2 and 1704.3.3 require the statement to name the systems and components subject to them. For construction not designed by a registered design professional, a qualified person approved by the building official may prepare the statement.

For an owner, the statement is the scope document. Send it to every agency you ask to price the work, so the bids cover the same items at the same frequency.

Worked example: which inspections apply to a three-story steel building?

This example shows how an owner can read Section 1705 against a simple building. It is hypothetical and does not replace the engineer's statement of special inspections.

The building: three stories, office use (Risk Category II), steel special moment frames, concrete slab on metal deck, isolated spread footings fully supported on soil, compacted fill under the slab on grade, and SFRM on beams, girders and columns. Each floor has 12,000 sq ft of sprayed floor assembly. The structural calculations place it in Seismic Design Category D.

Step 1: steel. Section 1705.2.1 applies to the steel frame, through the AISC 360 quality assurance requirements. Because the moment frames are a seismic force-resisting system in Seismic Design Category D, Section 1705.13.1.1 adds the AISC 341 requirements. The metal deck falls under Section 1705.2.3 and SDI QA/QC. If the frame is fabricated in a shop that is not an approved fabricator, Section 1704.2.5 requires inspection during fabrication; see shop fabrication inspection.

Step 2: concrete. The isolated spread footings meet exception 1 of Section 1705.3: the building is three stories, which is "three stories or less," and the footings are fully supported on earth. The slab on grade is nonstructural, so exception 3 applies. The slab on metal deck is structural, so Table 1705.3 applies to it: periodic reinforcement inspection, continuous sampling and testing, continuous placement inspection.

Step 3: soils. Section 1705.6 and Table 1705.6 apply to the compacted fill: continuous inspection during fill placement and compaction, and periodic checks of subgrade preparation and excavations.

Step 4: SFRM density samples. Section 1705.15.5 sets the rate for floor, roof and wall assemblies at not less than one sample for every 2,500 sq ft, or portion thereof, of sprayed area in each story. It sets the rate for structural members at not less than one sample for each type of structural member for each 2,500 sq ft of floor area, or portion thereof, in each story.

• Floor assemblies: 12,000 ÷ 2,500 = 4.8, rounded up to 5 samples per story, × 3 stories = 15 samples
• Members: 3 member types (beams, girders, columns) × 5 = 15 samples per story, × 3 stories = 45 samples
• Total density samples: 15 + 45 = 60

Step 5: structural observation. The building is Risk Category II, not a high-rise and not in Seismic Design Category E, so Section 1704.6.1 requires structural observation only if the structural engineer or the building official asks for it.

Result: structural steel and welding, high-strength bolting, steel deck, concrete on deck, compacted fill and SFRM inspections appear in the statement, with at least 60 SFRM density samples. The footings and slab on grade drop out under the concrete exceptions.

How does special inspection affect the schedule?

Special inspection affects the schedule because the work must stay open until it is inspected. Section 1704.2.2 requires the work to remain accessible and exposed until the required special inspections or tests are complete.

The common case is a concrete pour. Reinforcement inspection is periodic, but it has to happen before the concrete covers the bars. If the pour goes ahead first, the project may face coring, testing or an engineering review before the building official accepts the work.

Discrepancies follow a set path under Section 1704.2.4. The inspector brings them to the contractor's immediate attention for correction. If they are not corrected, the inspector reports them to the building official and the registered design professional before that phase of work is complete.

To keep inspections from holding up the work:

• Read the statement of special inspections before the first pour or steel delivery, and mark every continuous task.
• Agree the notice period and the request process with the agency before mobilization.
• On each request, give the location, the work type and the drawing or detail reference.
• Have the work ready, accessible and lit when the inspector arrives.
• Agree, before work starts, when the final report will be submitted. Section 1704.2.4 has the owner or owner's agent set that point in time.
• Collect contractor statements of responsibility for wind- and seismic-force-resisting systems before that work begins, as Section 1704.4 requires.

What special inspection does not do

Special inspection verifies listed work against the approved documents at the frequency the statement sets. It has clear limits that owners should understand before they rely on it.

• It does not replace the building department. Section 1704.2 makes it additional to the Section 110 inspections, and the building official still approves the work.
• It does not move quality responsibility. The contractor remains responsible for building to the documents; the special inspector reports whether the work conforms.
• It does not check the design. The inspector verifies against the approved construction documents. Design questions go to the registered design professional.
• Periodic inspection is a sample. An intermittent visit, or an "observe" task under AISC 360, does not see every weld or every bolt.
• It covers only the work in the statement. Items not listed in Section 1705, or not called out by the engineer or building official, are outside the inspector's scope.
• Local rules can change the details. Exceptions depend on the building official, and California's state agencies add their own amendments. The adopted code for your permit governs.

How SierraPoint Industries can help

SierraPoint Industries is an independent inspection agency providing special inspection, nondestructive testing (NDT), QA/QC oversight, Certified Welding Inspector (CWI) services and third-party auditing. It is accredited by the International Accreditation Service (IAS) as Special Inspection Agency SIA-442 (Type A) under IAS AC291 and ISO/IEC 17020:2012; the accredited scope includes structural steel and welding, high-strength bolting, concrete including field sampling, post-installed anchors, masonry and soils. See the special inspection services page and the accreditations page, and send your statement of special inspections through the contact page to request a proposal.

Frequently asked questions

Is special inspection the same as a building inspection?

Special inspection is separate from the building department's inspections. Section 1704.2 of the 2024 IBC and 2025 CBC says special inspections are in addition to the building official's inspections under Section 110. The building inspector checks permit milestones; the special inspector verifies listed tasks such as welding, concrete sampling or fill compaction.

Who pays for special inspection?

The owner pays, because Section 1704.2 requires the owner or the owner's authorized agent, other than the contractor, to employ the approved agency. A contractor may hire the agency only when the contractor is also the owner. Keeping the agency independent of the contractor is also a requirement of Section 1703.1.1.

Does every construction project need special inspection?

Not every project needs it. Section 1704.2 exempts minor work approved by the building official, Group U buildings accessory to a residence, and conventional light-frame construction under Section 2308, among others. The statement of special inspections prepared for your permit lists what applies.

What happens if a required special inspection is missed?

The work cannot simply be accepted. Section 1704.2.2 requires inspected work to stay accessible until inspection is complete, so covered work may need to be exposed, cored or tested, and the registered design professional and building official decide what evidence is acceptable. Report the miss to both promptly.

Who prepares the statement of special inspections?

The registered design professional in responsible charge prepares it under Section 1704.3, and the applicant submits it with the permit application under Section 1704.2.3. For work not designed by a registered design professional, the building official may approve another qualified person to prepare it.

When should an owner hire the special inspection agency?

Hire the agency before construction starts. Section 1704.2.1 requires the agency to submit documentation of its inspectors' competence to the building official before the start of construction, and the agency must be identified to the building official under Section 1704.2.

Sources

• International Code Council, 2024 International Building Code, Chapter 17 Special Inspections and Tests (Sections 1703.1.1, 1704.2 to 1704.6, 1705): https://codes.iccsafe.org/content/IBC2024V1.0/chapter-17-special-inspections-and-tests
• International Code Council, 2024 International Building Code, Chapter 2 Definitions (Section 202: special inspection, continuous and periodic special inspection, special inspector, approved agency, structural observation): https://codes.iccsafe.org/content/IBC2024V1.0/chapter-2-definitions
• International Code Council, 2025 California Building Code, Title 24 Part 2, Chapter 17: https://codes.iccsafe.org/content/CABC2025P1/chapter-17-special-inspections-and-tests
• International Code Council, 2025 California Building Code, Chapter 17A (scope, Section 1701A.1.1): https://codes.iccsafe.org/content/CABC2025P1/chapter-17a-special-inspections-and-tests
• California Building Standards Commission, Codes page (2025 Title 24 published July 1, 2025, effective January 1, 2026): https://www.dgs.ca.gov/BSC/Codes
• American Institute of Steel Construction, current standards (AISC 360, AISC 341): https://www.aisc.org/aisc/publications/current-standards/
• International Accreditation Service, special inspection agency accreditation (AC291, ISO/IEC 17020): https://www.iasonline.org/services/special-inspection-agencies/