WRB: ASTM D226 Type I felt (#15), ASTM E2556 Type 1 or 2 housewrap, or foam plastic insulating sheathing systems
2025 RCNYS §R703.2 Water-resistive barrier materialDescription
Water-resistive barriers must be at least: (1) No. 15 asphalt felt (ASTM D226 Type I); (2) ASTM E2556 Type 1 or 2 housewrap; (3) foam plastic insulating sheathing systems complying with R703.1.1; (4) an ASTM E331-tested assembly; or (5) other approved materials. WRB layers must be lapped horizontally — upper layer over lower by ≥ 2 in, with joints lapped ≥ 6 in. Accessory structures (sheds, playhouses) without insulation or interior finish are exempt.
Why this exists
Tyvek-style housewraps (ASTM E2556) are the residential default. They tear and require careful detailing around penetrations; 30# felt is more robust but heavier. The 2-in horizontal / 6-in joint laps are commonly missed by less-experienced installers — call them out on the wall detail.
Measurements
| Property | Operator | Value | Unit | Note |
|---|---|---|---|---|
horizontalLap | min | 2 | in | Upper-over-lower horizontal lap |
jointLap | min | 6 | in | Joint lap dimension |
Categories
Applies to
- Jurisdiction: New York State
Source
Solver enforcement
Browsable only — the solver does not currently enforce this directive (no spec-level data to check against). This entry exists so the architect personas can cite it in conversation and the user can read what the rule says.
Related directives
- Habitable space minimum ceiling height · IRC R305.1
- Wind design · IRC R301.2.1
- Seismic provisions · IRC R301.2.2
- Snow loads · IRC R301.2.3
- Floodplain construction · IRC R301.2.4
Last reviewed 2026-05-15.