Exterior Siding & Cladding Inspection

Per IRC R703.1, all exterior walls must be provided with a weather-resistant exterior wall envelope including a water-resistive barrier (WRB) behind the exterior cladding. The WRB must be installed shingle-fashion with upper courses overlapping lower courses by a minimum of 2 inches horizontally and 6 inches vertically per IRC R703.2. Housewrap products must comply with ICC-ES AC38 and be properly sealed at all seams and penetrations. Structural sheathing must be installed per the engineered design and fastened to manufacturer specifications.

1. Verify WRB is installed shingle-fashion with proper horizontal (2") and vertical (6") lap dimensions

2. Inspect all seams and penetrations for proper sealing with compatible tape or sealant

3. Confirm WRB is continuous and free of tears, punctures, or unsupported areas

4. Check that structural sheathing is properly fastened per nailing schedule

5. Verify WRB product is ICC-ES evaluated and installed per manufacturer instructions

- WRB installed with reverse laps allowing water infiltration behind the membrane

- Tears or punctures in WRB from construction activity left unrepaired

- Seams not taped or sealed especially around penetrations and window rough openings

- WRB left exposed beyond manufacturer's recommended UV exposure limit

Per IECC C402.2 and IRC N1102.1, continuous insulation (ci) must be installed on the exterior side of structural sheathing where required by the energy code for the applicable climate zone. Rigid foam insulation must be rated for exterior use and meet flame spread requirements per IBC 2603 (flame spread index 75 or less). Joints in rigid insulation must be staggered and taped or sealed to minimize thermal bridging. Insulation R-value must meet or exceed code requirements for the climate zone.

1. Verify continuous insulation type and R-value meets code requirements for the climate zone

2. Check that insulation joints are staggered and taped or sealed to minimize thermal bridging

3. Confirm insulation is mechanically fastened or adhered per manufacturer specifications

4. Inspect for gaps, compression, or missing insulation especially at corners and around penetrations

5. Verify insulation product meets flame spread requirements per IBC 2603

- Insulation R-value below code requirement for the applicable climate zone

- Gaps at joints and penetrations creating thermal bridges and moisture paths

- Insulation compressed by furring or cladding attachments reducing effective R-value

- Non-rated insulation products used without required thermal barriers

Per IRC R703.3 through R703.11, siding materials must be installed per the applicable code section for the material type. Lap siding must maintain minimum overlap per manufacturer specifications (typically 1-1/4 inches for wood and fiber cement). Fasteners must be corrosion-resistant and penetrate a minimum of 1-1/4 inches into wood studs or sheathing per IRC R703.4. Fiber cement siding must comply with ASTM C1186 and be fastened per manufacturer's evaluated installation instructions. Vinyl siding must comply with ASTM D3679 and be installed with allowance for thermal expansion.

1. Verify siding material is installed per manufacturer instructions and applicable IRC section

2. Check lap dimensions meet minimum overlap requirements at all courses

3. Confirm fastener type, size, and penetration depth meet code and manufacturer specifications

4. Inspect for proper clearance from grade — minimum 6 inches for wood and fiber cement per IRC R703.4

5. Verify vinyl siding has expansion allowance at all trim connections (1/4 inch typical)

- Insufficient lap overlap allowing wind-driven rain infiltration behind siding

- Fasteners overdriven in fiber cement causing cracking or loss of holding power

- Siding installed too close to grade allowing moisture wicking and decay

- Vinyl siding face-nailed too tightly preventing thermal expansion movement

Per IRC R703.4 and R703.8, approved corrosion-resistant flashing must be installed at all wall-to-roof intersections, above all projecting wood trim, at wall-to-deck connections, and at the top and sides of all window and door openings. Kick-out flashing (diverter flashing) is required where roof-to-wall intersections terminate at an eave per IRC R703.4. Flashing must extend a minimum of 2 inches beyond the face of the cladding and direct water outward to the exterior. Self-adhered flashing membranes must comply with AAMA 711.

1. Inspect all roof-to-wall intersections for proper step flashing and counter-flashing

2. Verify kick-out (diverter) flashing is installed at all roof-to-wall terminations at eaves

3. Check window and door head flashing extends beyond the cladding face with proper end dams

4. Confirm deck ledger flashing directs water away from the wall assembly

5. Inspect flashing integration with WRB — flashing must be shingled into the WRB system

- Missing kick-out flashing at roof-to-wall terminations causing concealed water damage

- Window head flashing not properly integrated with WRB above

- Deck ledger flashing omitted or improperly installed allowing water behind siding

- Step flashing omitted or underlapped instead of overlapped with shingle courses

Per IRC R703.4 and ASTM C1193, all siding joints, penetrations, and transitions must be sealed with compatible sealants or have approved mechanical joint systems. Sealant joints must be properly sized — minimum 1/4 inch wide and 1/4 inch deep — with backer rod installed for joints wider than 1/2 inch. Sealant must be compatible with adjacent materials and rated for exterior use per ASTM C920. Butt joints in lap siding must occur over studs or solid blocking and be properly sealed or flashed.

1. Inspect all sealant joints for proper width, depth, and tooled concave profile

2. Verify backer rod is installed in joints wider than 1/2 inch to control sealant depth

3. Check sealant adhesion at random locations — no peeling, cracking, or cohesive failure

4. Confirm butt joints in siding are located over structural support and properly sealed

5. Verify sealant product compatibility with substrate materials (check manufacturer data)

- Sealant joints too thin or too deep resulting in premature adhesive or cohesive failure

- Missing backer rod in wide joints causing three-sided adhesion and sealant tearing

- Incompatible sealant used on certain substrates (silicone on porous materials)

- Butt joints not located over framing members allowing flexion and joint failure

Per IBC 1406 and NFPA 285, exterior wall assemblies on buildings greater than 40 feet in height must pass the NFPA 285 fire propagation test when using combustible materials. In wildfire-urban interface (WUI) zones, exterior cladding must comply with IBC Chapter 7A or local WUI codes requiring ignition-resistant materials. Per IBC Table 602, exterior wall fire-resistance ratings depend on fire separation distance — walls less than 5 feet from property lines require 1-hour rating with 0-foot opening protection.

1. Verify exterior wall assembly has required fire-resistance rating based on fire separation distance

2. Confirm NFPA 285 compliance documentation is available for buildings over 40 feet with combustible cladding

3. Check WUI zone compliance if applicable — ignition-resistant or noncombustible materials used

4. Inspect fire blocking within the cladding cavity per IRC R302.11 at each floor level and 10-foot intervals

5. Verify material flame spread and smoke development ratings meet IBC Chapter 8 requirements

- Missing fire blocking in rainscreen or ventilated cladding cavities at floor lines

- Combustible cladding on buildings over 40 feet without NFPA 285 test documentation

- Non-compliant materials used in WUI zones increasing wildfire vulnerability

- Insufficient fire separation distance without required fire-resistance-rated wall assembly

Per IRC R703.1 and ASTM E331, the complete exterior wall assembly must resist water penetration under wind-driven rain conditions. Ventilation gaps behind cladding (rainscreen principle) are recommended per best practice and required in some jurisdictions per IRC R703.1.1. All penetrations including utilities, hose bibs, vents, and electrical outlets must be sealed with appropriate boots, collars, or sealants. Weep holes or drainage provisions must be maintained at the base of wall assemblies per manufacturer and code requirements.

1. Inspect the complete wall assembly for visual signs of water infiltration or staining

2. Verify drainage plane continuity from top of wall to weep screed or base flashing

3. Check all utility penetrations for proper sealing with approved materials

4. Confirm weep holes or drainage provisions are open and functional at base of wall

5. Inspect ventilation gaps in rainscreen assemblies for proper spacing and clear airways

- Blocked weep holes at base of wall preventing drainage of incidental moisture

- Utility penetrations unsealed allowing direct water entry behind cladding

- Missing drainage mat or rainscreen gap in back-ventilated cladding systems

- Caulk or mortar applied over weep openings during finishing trades