International Building Code (IBC)
IBC Chapter 14 provides general product and installation requirements for cladding.
Product Requirements (1403)
Products must be certified and labeled to show they conform to their established ASTM standard:
Vinyl Siding
ASTM D3679 — 1403.8
Insulated Vinyl Siding
ASTM D7793 1403.14
Polypropylene Siding
ASTM D7254 — 1403.11
Backed Vinyl Siding
ASTM D7445 — CODE COMPLIANCE REPORTS
- Backed vinyl siding is not addressed in the IRC or IBC. Building officials should rely on code compliance reports for backed vinyl siding in accordance with ASTM D7445 to assure code compliance.
- In northern climate zones, according to Table 1404.3(3) counts vinyl siding and polypropylene siding as vented cladding. Vented claddings provide excellent moisture management characteristics which also allow the elimination of vapor retarders.
Installation Requirements
- IBC 1404.15 In general, vinyl siding and insulated vinyl siding are installed 16" on center using roofing nails (siding nails), although variations can be done including other approved fasteners like staples and screws. Prescriptive requirements for vinyl siding installation include that non-corrosive roofing nails that can penetrate the nailable substrate at least between 1 - 1/4" and must be spaced no more than 16" on center for horizontal siding and 12" on center for vertical siding and according to the manufactured installation instructions.
- IBC 1404.18 Polypropylene siding panels range in size and are unique. Manufacturer's instructions should be reviewed because in many cases fastener spacing may be less than 10" on center. It must be installed over some type of wood sheathing.
Considerations and Conditions for use in High-density Developments with Noncombustible Construction
- IBC 1405 In general, polymeric exteriors are allowed in all types of construction, including noncombustible construction, although test results must be demonstrated in compliance to 1405 IBC.
- Table 601 and 705.5 place certain fire resistance ratings on walls depending on the occupancy, type, density (distance to lot line) and size of the building based on ASTM E119 tests.
- Polymeric exteriors are a part of many ASTM E119-rated assemblies.
- Vinyl siding, insulated vinyl siding and polypropylene siding are allowed to be part of 722’s calculated fire resistance approach through Table 722.6.2(3).
- 1405 provides the use of polymeric exteriors (and other combustible cladding) with noncombustible construction (Types I, II, III, IV).
- IBC 1405.1.1.1 If polymeric exteriors are used with noncombustible construction (Types I, II, III, IV), they must be tested according to NFPA 268 and perform to certain levels depending on the building’s fire separation distance. This test method demonstrates the ability of other combustible materials to not ignite under certain radiant heat conditions.
- 1403.11.2 and IBC 140.3.11.2 When installing polypropylene siding in high-density settings (less than 5' to property line), the product must have a certified ASTM E84 test report, based on the code requirement. Note: This requirement does not apply to certain walls that are perpendicular to the fire separation distance measurement, like townhouse front and rear elevations.
Building Codes and Product Certification / Technical Information
2025 Polymeric Cladding Building Code Reference Guide
An at-a-glance breakdown of the International, Florida and Canadian building codes, performance information, and installation requirements for polymeric cladding.
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