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Special inspections: what IBC Chapter 17 requires and who does what

Direct answer: Special inspections are third-party inspections and tests of critical construction work, such as concrete, steel, masonry, soils, and deep foundations. They are done by a qualified special inspector working for an approved agency. They are in addition to the building department's own inspections. Under IBC Chapter 17, the owner (not the contractor) hires the agency, and the design professional lists the required inspections in a Statement of Special Inspections before the permit is issued (IBC 2024 §§1704.2, 1704.2.3, 1704.3).

Edition note: citations are to the 2024 IBC (ICC official text; readable copy via UpCodes). Local adoptions and amendments vary, and section numbers move between editions. NYC, for example, runs its own Chapter 17 (NYC BC 2022 Ch. 17).

What is a special inspection?

The IBC defines four key terms (IBC 2024 Ch. 2 definitions):

TermIBC 2024 definition (quoted)
Special inspection"Inspection of construction requiring the expertise of an approved special inspector in order to ensure compliance with this code and the approved construction documents."
Special inspector"A qualified person employed or retained by an approved agency and approved by the building official as having the competence necessary to inspect a particular type of construction requiring special inspection."
Approved agency"An established and recognized organization that is regularly engaged in conducting tests, furnishing inspection services or furnishing product evaluation or certification where such organization has been approved by the building official."
Structural observation"The visual observation of the structural system by a registered design professional for general conformance to the approved construction documents."

Special inspection vs. building department inspection vs. structural observation

Who performs itWhat it coversCode
Building official inspectionsBuilding departmentRequired inspections such as footing and foundation, concrete slab and under-floor, and others listed in §110.3IBC 2024 §110.3
Special inspections and testsApproved agency / special inspector hired by the ownerWork types listed in §1705, per the Statement of Special InspectionsIBC 2024 §§1704.2, 1705
Structural observationA registered design professional employed by the ownerVisual observation of representative locations of structural systems, details and load paths. "Does not include or waive" §110 inspections or §1705 special inspections.IBC 2024 §1704.6

How IBC Chapter 17 is organized

SectionTopicSource
1701General: scopeIBC 2024 Ch. 17
1702New materialssame
1703Approvals: approved agency independence, equipment, personnel; labelingsame
1704Special inspections and tests, contractor responsibility, structural observationsame
1705Required special inspections and tests, by material and systemsame
1706–1709Design strengths of materials; alternative test procedure; in-situ load tests; preconstruction load testsIBC 2024 Ch. 17

Who does what under §1704

PartyResponsibilitySection
Owner / owner's authorized agent (other than the contractor)Employs one or more approved agencies and identifies them to the building official§1704.2
Approved agencyMust be "objective, competent and independent from the contractor responsible for the work being inspected" and disclose possible conflicts of interest§1703.1.1
Approved agencyGives the building official written documentation of each special inspector's competence before construction starts§1704.2.1
RDP in responsible chargePrepares the Statement of Special Inspections§1704.3
ApplicantSubmits the Statement as a condition for permit issuance§1704.2.3
Contractor (wind/seismic systems listed in the SSI)Submits a written statement of responsibility before starting that work§1704.4
Approved agencyReports to the building official and the RDP. Discrepancies go to the contractor immediately, then to the building official and RDP if not corrected. Submits the final report.§1704.2.4

All rows: IBC 2024 Ch. 17.

What requires special inspection (IBC §1705)

§1705 sectionWorkNotes from the code text
1705.1.1Special casesUnusual work, such as alternative materials, unusual design applications, or systems installed per additional manufacturer instructions
1705.2SteelStructural steel per AISC 360 QA (1705.2.1); stainless (1705.2.2); CFS deck (1705.2.3); open-web joists and joist girders (1705.2.4); CFS trusses spanning 60 ft or more (1705.2.5); metal building systems (1705.2.6)
1705.3ConcreteTable 1705.3, e.g., reinforcement placement (periodic); fresh-concrete sampling, slump, air and temperature (continuous); placement (continuous); curing (periodic)
1705.4MasonryPer the QA program of TMS 402 and TMS 602, with exceptions
1705.5WoodPrefabricated elements per §1704.2.5; high-load diaphragms; trusses spanning 60 ft or more; mass timber (Table 1705.5.3)
1705.6SoilsTable 1705.6: bearing, excavation depth, fill classification, fill placement and density (continuous), subgrade
1705.7–1705.8Driven and cast-in-place deep foundationsTables 1705.7 / 1705.8
1705.9Helical pilesContinuous special inspection during installation
1705.10Deep-foundation structural integrityEngineering assessment with tests (e.g., ASTM D4945, D5882, D6760, D7949) where integrity is in doubt
1705.11Fabricated itemsPer §1704.2.5 (unless the fabricator is approved)
1705.12Wind resistanceExposure B with V ≥ 150 mph; Exposure C or D with V ≥ 140 mph
1705.13–1705.14Seismic resistance and seismic testingIncludes designated seismic systems, architectural and MEP components, storage racks, isolation systems
1705.15Sprayed fire-resistive materials (SFRM)
1705.16Intumescent fire-resistive materialsPer AWCI 12-B
1705.17EIFS
1705.18Fire-resistant penetrations and joints
1705.19Testing for smoke controlTester needs fire-protection engineering, mechanical engineering and air-balancer certification expertise
1705.20Sealing of mass timber

All rows: IBC 2024 §1705.

The special inspection process, step by step

  1. Design: the RDP identifies required special inspections and prepares the Statement of Special Inspections (§1704.3). See our SSI guide and template.
  2. Permit: the applicant submits the SSI as a condition for permit issuance (§1704.2.3).
  3. Hire: the owner employs the approved agencies and identifies them to the building official (§1704.2). The agency documents inspector qualifications before construction (§1704.2.1).
  4. Before wind/seismic work: each responsible contractor files a statement of responsibility (§1704.4).
  5. During construction: work stays accessible and exposed until inspected (§1704.2.2). The agency inspects continuously or periodically as scheduled.
  6. Reports and discrepancies: reports go to the building official and the RDP. Uncorrected discrepancies are escalated before that phase of work is complete (§1704.2.4).
  7. Closeout: the final report documents the required inspections and the correction of discrepancies (§1704.2.4), plus certificates under §1704.5 where applicable.

Source for all steps: IBC 2024 Ch. 17.

How cities layer on top of Chapter 17

FAQ

What is a special inspection?

Under the IBC, it is inspection of construction that requires an approved special inspector's expertise to ensure compliance with the code and the approved construction documents (IBC 2024 Ch. 2). It is in addition to the building official's own inspections (§1704.2).

What does a special inspector do?

A special inspector works for an approved agency and is approved by the building official for a particular type of construction (IBC 2024 Ch. 2). They inspect the work listed in the Statement of Special Inspections, continuously or periodically. The agency reports results to the building official and the RDP and flags discrepancies to the contractor (§1704.2.4).

Who hires the special inspector?

The owner or the owner's authorized agent, other than the contractor, unless the contractor is also the owner (IBC 2024 §1704.2). The agency must be independent from the contractor whose work it inspects (§1703.1.1).

What will most likely require a special inspection?

Structural concrete, structural steel, masonry, soils and fill, deep foundations, and fabricated items, plus wind and seismic systems where triggered and fire-protection items like SFRM and firestopping (IBC 2024 §1705).

What are the four types of inspections?

The IBC doesn't use a fixed "four types" list. On a typical commercial job you will see four kinds of inspection activity: building-department inspections (§110), continuous special inspection, periodic special inspection, and structural observation by an RDP (§1704.6). Tests (§1705) sit alongside these (IBC 2024 Ch. 1; Ch. 2; Ch. 17).

Is structural observation the same as special inspection?

No. Structural observation is a visual check for general conformance by an RDP, and it "does not include or waive" the §1705 special inspections (IBC 2024 §1704.6).

Catch the Chapter 17 items your spec forgot to mention

When SpecProven drafts an inspection plan from your project manual, it adds a note wherever a section is silent on a usual IBC Chapter 17 special inspection (how it works). After the plan is built, it matches incoming inspection reports to the plan lines they prove. A paid pilot is $2,900 to start and covers four projects, then $500 per project per month after the four included. Pricing.

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