Required Inspection Types for Residential Construction Under IRC 2024

Quick Answer

IRC 2024 Section R109 requires inspections at defined stages of construction before work is concealed. At minimum, the building official must be notified and given the opportunity to inspect at foundation, framing, plumbing, mechanical, electrical, energy/insulation, and final stages. Additional inspections—including fireplace, floodplain, and special inspections—apply when those systems or conditions are present.

Under IRC 2024, no work may be concealed until the applicable inspection has been completed and approved. A contractor who covers framing before the framing inspection passes risks being ordered to uncover the work at their own expense.

What IRC 2024 Actually Requires

Section R109.1 lists the required inspections for one- and two-family dwellings and townhouses. The inspection schedule is organized around the phases of construction at which code-critical elements are visible and accessible before being covered by subsequent work. The following inspections are required under R109.1 subsections:

Foundation inspection (R109.1.1): The foundation inspection must be made after poles or piers are set or trenches or basement areas are excavated and any required forms or reinforcing steel is in place, but before any concrete is poured. The inspector confirms footing size, depth, reinforcement, and setback from property lines. In seismic and frost zones, the inspector also verifies footing depth below frost line and any required seismic reinforcement.

Concrete slab or under-floor inspection (R109.1.2): This inspection occurs after the sub-floor area is accessible and any slab reinforcing, vapor retarder, rigid insulation, and under-slab plumbing rough-in are in place, before concrete is poured. Missing this inspection is particularly costly because it requires jackhammering slab to expose concealed plumbing after the fact.

Lowest floor elevation inspection (R109.1.3): Required in flood hazard areas after the lowest floor is established, to confirm compliance with flood elevation requirements. The inspector documents the elevation and the measurement method, which becomes part of the permit record used for flood insurance purposes.

Frame inspection (R109.1.4): The framing inspection must be made after the roof deck or sheathing, all framing, fire blocking, draft stopping, and bracing are in place, and after all pipes, chimneys, and vents to be concealed are complete, but before any insulation is applied. The frame inspection is one of the most comprehensive inspections in residential construction. Inspectors review structural member sizes and spans, header sizing, bearing points, joist hangers, post-to-beam connections, shear wall sheathing nailing, hold-down hardware, fire blocking at floor-to-wall intersections, and draft stopping in concealed attic and floor spaces.

Plumbing inspection (R109.1.5): Plumbing rough-in inspection is made after the rough-in plumbing, drain, waste, and vent (DWV) system is in place, after required underground plumbing is installed, and before the system is covered or concealed. The inspector verifies DWV pipe sizing, slope, cleanout locations, vent termination, and pressure test results on the system.

Mechanical inspection (R109.1.6): Required after mechanical rough-in, including ductwork, equipment rough-in, and combustion air provisions, are complete and before concealment. The inspector reviews duct sizing, clearances, combustion air openings, and equipment installation in the mechanical chase or mechanical room.

Gas and fuel piping inspection (R109.1.7): Gas piping must be inspected and pressure-tested before concealment. IRC Section R109.1.7 specifies that the fuel-gas piping inspection must include a test of the system at not less than 1½ times the working pressure, but not less than 3 psi, with a duration of not less than 10 minutes without loss of pressure.

Energy efficiency inspections (R109.1.8): An inspection of the building’s thermal envelope, insulation, fenestration, and mechanical systems is required to verify compliance with the energy provisions of the IRC. In most jurisdictions this is performed as part of the insulation inspection, where the inspector confirms installed R-values, continuous insulation layers, air barrier continuity, and window U-factors before the insulation is covered by drywall.

Other required inspections (R109.1.9): Additional inspections are required for masonry fireplaces, solid fuel-burning appliances, and any other system designated by local amendment as requiring inspection at a specific stage.

Final inspection (R109.1 generally): The final inspection is performed after all construction, alteration, or work authorized by the permit is complete. The inspector confirms all previous inspections have been approved, all permit conditions have been met, and the building is safe to occupy.

Why This Rule Exists

The staged inspection system exists because building construction proceeds in layers, and many of the most important structural, fire protection, and life safety elements are permanently concealed once subsequent construction layers are applied. A footing that is too shallow cannot be corrected after concrete is poured without demolishing the foundation. Framing deficiencies hidden behind drywall can go undetected for decades until a structural failure exposes them. Plumbing concealed in a slab that was never pressure-tested can leak for years before saturation of the subgrade causes visible settlement or damage.

The inspection system also creates a documented record of construction quality at each stage. That record has value in subsequent transactions, insurance claims, and litigation where the quality of original construction is at issue. A permit file with approved inspections at each required stage is strong evidence that the work met the adopted code at the time of construction.

What the Inspector Checks at Rough and Final

At the foundation inspection, the inspector measures footing dimensions against the approved plans, verifies reinforcing bar size and placement, checks footing depth against the frost-depth requirement in the local building code, and confirms the footing is not in fill soil unless the plans specifically account for fill compaction. The inspector may order a soil bearing test if conditions suggest the native soil does not meet the assumed bearing capacity.

At framing inspection, the inspector works from a checklist that typically includes: header sizes over all openings against the IRC header span tables; rafter and joist spans against the prescriptive span tables in the IRC or the approved engineered drawings; joist hanger installation at all bearing conditions specified in the plans; shear wall nailing patterns; hold-down anchor bolt installation; fire blocking at all required locations (top and bottom of wall cavities, at horizontal offsets, and at penetrations through floor and ceiling assemblies); stairway rise, run, and handrail requirements; and rough opening sizes for egress windows in sleeping rooms.

At plumbing rough-in, the inspector witnesses or reviews the pressure test documentation, checks DWV slope (minimum ⅛ inch per foot for horizontal runs), verifies cleanout locations at all required points, and confirms vent pipe termination above the roofline at the minimum height required by R903.

At final inspection, the inspector confirms smoke alarms are installed in all required locations, carbon monoxide alarms are installed where required by R315, all egress windows in sleeping rooms meet the minimum opening area and height requirements, handrails and guardrails are properly installed, and all appliances and equipment have been installed and are functional.

What Contractors Need to Know

The most important operational practice around inspections is scheduling them early enough to avoid work delays. In busy jurisdictions, inspection slots may be 48 to 72 hours out. If a framing inspection is needed before insulation can proceed, and the next available inspection slot is three days away, that is three days of lost productivity on the job. Savvy project managers book inspection slots as soon as the work is scheduled, then confirm readiness the day before rather than calling for an inspection after the work is ready.

Contractors must also understand that an inspection rejection means no further work can proceed in the affected area until the rejection is resolved and a re-inspection is approved. A rejected framing inspection that requires corrections to hold-down hardware before re-inspection can stall insulation, mechanical, and electrical rough-in simultaneously. Thorough pre-inspection checklists run by a superintendent or lead carpenter before calling for inspection reduce rejection rates and keep projects on schedule.

Gas system pressure tests are a field management item that many residential contractors handle inconsistently. The test must be performed at the required pressure and held for the required duration, and the contractor must be present with the inspector or provide documented test results. Having a pressure gauge on-site and a test log ready for the inspector is a professional practice that builds credibility with the inspection authority and speeds the inspection process.

Contractors working in jurisdictions that require special inspections—third-party inspections by certified inspectors for concrete placement, high-strength bolting, or other designated elements—must coordinate the special inspector’s schedule with the construction timeline. Special inspections are distinct from building official inspections and must be documented in a special inspection program approved by the building official before construction begins.

What Homeowners Get Wrong

Homeowners frequently misunderstand who is responsible for scheduling inspections. The permit holder—which is the building owner in most residential permit situations—is responsible for notifying the building official when work is ready for inspection. If the homeowner has hired a general contractor, the contractor typically handles inspection scheduling, but the homeowner should confirm this is occurring. Discovering at the end of a project that multiple required inspections were not called is not an unusual situation, and correcting it after the fact can be very disruptive.

Homeowners sometimes allow contractors to proceed with work before an inspection is approved because the contractor says the work is “obviously correct” or that “inspectors never catch anything anyway.” This is poor practice regardless of the contractor’s confidence level. If uninspected work is later rejected, the cost of correction falls on the owner, not the contractor who pushed ahead without inspection approval.

The energy inspection is the inspection homeowners least understand and most frequently neglect. Insulation and air sealing that is covered by drywall before the energy inspection is approved must either be uncovered or accepted on a certification-only basis, which is a less defensible compliance path and may not be accepted in all jurisdictions. Schedule the insulation and energy inspection before drywalling begins.

State and Local Amendments

Many jurisdictions add inspection requirements beyond those listed in R109. California requires special inspections for seismic bracing elements including shear walls, hold-down hardware, and post-installed anchors in concrete. Florida requires an additional structural inspection of the completed roof covering to verify hurricane-rated installation in wind-borne debris regions. Some counties in high-fire-hazard zones require an exterior finish inspection to verify fire-resistant siding and roof materials were installed as specified.

Several states require mandatory third-party energy inspections or blower-door tests to verify air sealing performance before the certificate of occupancy is issued. These states have adopted the energy code’s mandatory air leakage testing requirement rather than accepting the prescriptive compliance path. Oregon, Washington, and Minnesota all require blower-door testing as part of energy compliance for new residential construction. If your jurisdiction requires this, coordinate the test with the insulation and energy inspection so the inspector can witness the test result.

Jurisdictions that have adopted local amendments creating a “pre-drywall inspection” or “wall board inspection” as a formal required stage add an inspection point that covers all rough-in work—framing, plumbing, mechanical, electrical, insulation, and energy—in a single visit before drywall is applied. These combined inspections reduce the total number of inspection calls while ensuring nothing is covered prematurely.

When to Hire a Professional

Projects that require special inspections—typically high-load conditions such as engineered lumber systems, moment frames, shear walls with nailing patterns specified by a structural engineer, or post-installed anchors in concrete—require a third-party special inspector certified in the applicable area. The building official will specify what special inspections are required in the permit approval. Failure to engage a qualified special inspector when required is a permit violation that can result in rejection of the final inspection and refusal to issue a certificate of occupancy until the required special inspection reports are provided.

Homeowners managing their own construction as owner-builders should consider hiring a construction manager or owner’s representative to handle inspection scheduling and coordinate corrections. The inspection process is not complicated for experienced contractors, but it requires consistent attention to scheduling and sequencing. A single missed inspection that requires uncovering completed work can cost far more than the management fee for professional oversight of the process.

Where a jurisdiction requires a licensed design professional to prepare the plans, the design professional should also be engaged to perform construction administration visits at key inspection stages. A licensed architect or engineer who designed the structure is well-positioned to confirm that the work matches the approved drawings and to resolve any field conditions that arise during construction that require design modification.

Common Violations Found at Inspection

• Framing covered by insulation or drywall before the framing inspection was approved, requiring removal of covering material to allow inspection.
• Concrete poured before the foundation inspection was completed and approved, requiring core samples or destructive testing to verify footing dimensions and reinforcement.
• Gas piping concealed in walls before pressure test was witnessed by the inspector or documented test results were provided.
• Under-slab plumbing covered by concrete without a slab inspection, requiring core drilling to access and inspect the system.
• Insulation installed and drywall applied before the energy inspection, preventing verification of installed R-values, air barrier continuity, and window labeling.
• Missing fire blocking at required locations in the framing, discovered at framing inspection when the contractor assumed it was not required in that wall type.
• Special inspections required by the permit approval not performed or not documented, preventing final inspection approval.
• Smoke alarms missing from required locations or not interconnected as required by IRC R314, discovered at final inspection.