System Overview:
The Western 1-Kote® System is a code-recognized exterior stucco wall assembly utilizing Western 1-Kote cementitious basecoats in conjunction with approved weather-resistive barriers, metal lath, and compatible finish systems.

Recognized under IAPMO UES ER-382, the system provides an alternative to conventional three-coat stucco assemblies while maintaining compliance with applicable building codes. The system may be configured with standard or premium basecoat options and may incorporate the optional Crack Resistant System (CRS) for enhanced crack resistance performance.

The Western 1-Kote System is adaptable to both non-insulated and insulated wall assemblies in accordance with ER-382.

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System Intent and Performance:
The Western 1-Kote System is engineered to:

• Provide a minimum 3/8-inch cementitious basecoat over approved lath assemblies in accordance with ER-382.

• Comply with IAPMO UES ER-382 as an alternative to conventional three-coat stucco systems.

• Deliver a fiber-integrated basecoat designed to reduce shrinkage-related cracking compared to traditional field-mixed plaster systems.

• Accommodate a range of architectural finish systems, including cementitious and acrylic coatings.

• Allow integration of performance-enhancing components, including premium basecoat formulations, Premium Acrylic Finish systems, continuous insulation, and the optional Crack Resistant System (CRS).

• Assemblies include multiple fire-resistance-rated wall configurations in accordance with ER 382.

• NFPA 285-compliant assemblies are available when constructed in accordance with approved configurations. Refer to ER-382 for full assembly listings and requirements.

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When configured with the Crack Resistant System (CRS), the assembly incorporates a reinforced basecoat layer with embedded alkali-resistant mesh designed to enhance crack resistance characteristics and surface durability.

The Western 1-Kote System provides a code-recognized exterior plaster assembly adaptable to multiple wall configurations while maintaining compliance with applicable building codes and referenced ASTM standards. The system is not structural and does not eliminate cracking resulting from structural movement.

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System Components:
Basecoat Options:

• Standard: Western 1-Kote Gray Concentrate or Sanded Gray.

• Premium: Western 1-Kote Premium Gray Concentrate or Premium Sanded Gray. 

• Minimum thickness: 3/8 inch over approved lath assemblies in accordance with ER-382.

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Weather-Resistive Barrier (WRB):

• Code-approved weather-resistive barrier installed in accordance with ER-382 and applicable building code requirements.

 

Metal Lath & Accessories:

• Metal lath complying with ASTM C847.

• Installation in accordance with ASTM C1063.

• Control and expansion joints as required by code.

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Exterior Finish Options:

• WBP Exterior Stucco Finish

• WBP Premium Acrylic Finish + PAF Primer

• Exterior Finish Coatings by additional listees from IAPMO UES ER-382

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Premium Acrylic Finish assemblies requiring 7-, 10-, or 15-year warranty tiers shall incorporate PAF Primer in accordance with WBP installation requirements.

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Optional Enhancement: Crack Resistant System (CRS).

• The Crack Resistant System (CRS) consists of BPS Armor CRS reinforcing basecoat and alkali-resistant fiberglass mesh installed at a minimum 1/16-inch embedment thickness.

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When incorporated into the Western 1-Kote System, CRS elevates the assembly to the reinforced warranty tier in accordance with the warranty schedule. CRS enhances crack resistance characteristics but is not structural reinforcement.

Typical System Configuration:
A typical Western 1-Kote System assembly consists of:

1. Approved structural substrate (wood-based sheathing, gypsum sheathing, concrete, or masonry as permitted by ER-382).

2. Code-compliant weather-resistive barrier.

3. Self-furred metal lath mechanically fastened in accordance with ASTM C1063.

4. Western 1-Kote basecoat applied to a minimum thickness of 3/8 inch.

5. Optional Crack Resistant System (CRS), when specified.

6. Selected exterior finish coating.

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Continuous insulation boards, where permitted under ER-382, may be incorporated within the assembly.

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Substrate Requirements:
Substrates shall comply with the requirements of ER-382 and applicable building codes. Substrates permitted under ER-382 include walls of:

• Concrete

• Masonry

• Wood structural panel wall sheathing

• Fiberboard

• Light-frame construction covered with gypsum board

• Foam plastic insulation board

• Mineral wool insulation board

• Insulated concrete forms (ICFs)

• Similar approved substrates in accordance with ER-382

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Light-frame wall assemblies shall utilize wood studs with a minimum specific gravity of 0.50 or minimum 0.035-inch-thick (No. 20 gage) steel studs spaced a maximum of 24 inches on center.
Application of cement plaster shall be performed over substrates prepared in accordance with Section 3.2.3 of ER-382.
Substrates shall be structurally sound, properly braced, and free of conditions that may adversely affect system performance.

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Environmental Conditions:
Components shall not be installed when surface or ambient temperatures are below 40°F (4.4°C) or above 100°F (38°C).
All cementitious components require a minimum of forty-eight (48) hours moist curing. Extended curing may be required under conditions of heat, wind, or low humidity.
Protect installed materials from freezing, rapid drying, or inclement weather until adequately cured.

 

System Limitations:
The Western 1-Kote System:

• Is not structural.

• Does not eliminate cracking caused by structural movement.

• Requires proper control joint placement in accordance with ASTM C1063 or as specified by the project designer or architectural specification.

• Must be installed in accordance with ER-382 and WBP installation requirements.

• Requires installation by qualified applicators.

• System performance is dependent upon compliance with WBP installation guidelines and integration within approved stucco assemblies.

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Code and Standards:
The Western 1-Kote System is recognized and evaluated under:

• IAPMO UES ER-382

• 2024, 2021, 2018 & 2015 International Building Code (IBC)

• 2024, 2021, 2018 & 2015 International Residential Code (IRC)

• 2025 & 2022 California Building Code (CBC)

• 2023 Florida Building Code (FBC)

• Applicable ASTM Standards:

• ASTM C926 — Application of Portland Cement-Based Plaster

• ASTM C1063 — Installation of Lathing and Furring to Receive Portland Cement-Based Plaster

• ASTM C847 — Metal Lath

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System Positioning:
The Western 1-Kote System provides a flexible, code-recognized exterior stucco solution adaptable to conventional, insulated, and performance-enhanced wall assemblies.

Through the selection of premium basecoat formulations, Premium Acrylic Finish systems, and the optional Crack Resistant System (CRS), the assembly may be configured to address project-specific objectives related to crack resistance, durability, and extended warranty coverage while maintaining compliance with ER-382.

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Warranty Schedule Matrix:
The warranty schedule outlines the available warranty terms for the Western 1-Kote System based on basecoat selection, finish system configuration, and incorporation of the Crack Resistant System (CRS). 
Warranty duration is dependent upon compliance with WBP installation requirements and proper integration of system components as defined in this Technical Data Sheet and ER-382. ​