PROSOCO BMC II White/Pastel Base Color Coating - 5 Gallon

PROSOCO BMC II White/Pastel Base — Breathable Masonry Water Repellent Color Coating

PROSOCO Breathable Masonry Coating II (BMC II) is a silicone emulsion-based water repellent color coating specifically engineered for masonry substrates. It combines the aesthetic performance of a high-quality paint with the protective functionality of a breathable water repellent, making it suitable for contractors working on both historic and contemporary masonry construction. BMC II allows water vapor to escape from within the masonry while blocking destructive liquid water intrusion, preserving the substrate's appearance and extending its service life. This product is available as a special order item; production lead times may apply.

Unlike most conventional paints, BMC II's unique silicone emulsion formulation delivers superior resistance to weathering — including UV exposure, moisture, and soiling — resulting in a more durable and longer-lasting finish. Its field-proven performance is documented on landmark projects including the U.S. Capitol and numerous historic and contemporary buildings across the United States and Europe. No primer is required, simplifying surface preparation and reducing labor time on the job site.

Technical Specifications

Key Features & Benefits

Highly Vapor Permeable

BMC II allows water vapor to escape from within masonry while simultaneously blocking liquid water penetration. This breathability is critical for masonry substrates where trapped moisture can cause cracking, spalling, and long-term structural degradation. It meets and exceeds the requirements of ASTM E 2357, providing contractors with a performance-verified solution.

Silicone Emulsion Formula for Durability

The unique silicone emulsion formulation makes BMC II more resistant to UV exposure, moisture, and soiling than most conventional paints. This translates to a longer-lasting finish that requires less frequent recoating, reducing lifecycle maintenance costs for building owners and contractors.

No Primer Required

BMC II needs no primer coat, streamlining surface preparation and reducing material and labor costs. A priming coat may be applied if desired using PROSOCO Siloxane WB at a dilution ratio of one part product to 19 parts water, with BMC II applied within 48 hours of primer application.

Broad VOC Compliance

BMC II is compliant with all national, state, and district AIM VOC regulations, with a VOC content of 100 g/L maximum. Contractors working across multiple jurisdictions can specify this product with confidence that it will meet local regulatory requirements.

Excellent UV Stability and Color Retention

BMC II delivers excellent UV stability, hiding power, and exceptional color retention. Contractors can rely on consistent, long-lasting color performance on exterior masonry exposed to direct sunlight and weathering.

Easy Application — Interior or Exterior Use

The coating can be applied with a roller, brush, or airless sprayer, giving crews flexibility depending on job size and substrate geometry. It produces no harsh odors and is suitable for both interior and exterior masonry applications.

Common Applications

Historic Masonry Restoration

BMC II has been field-proven on the U.S. Capitol and other landmark historic buildings across the U.S. and Europe, making it a trusted choice for restoration contractors working on historically sensitive masonry facades.

Concrete Masonry Unit (CMU) Block Walls

Suitable for burnished, smooth, split-faced, and ribbed architectural concrete block, with coverage ranging from 100–150 sq. ft. per gallon depending on surface texture.

Concrete, Precast Panels, and Cast-in-Place Concrete

Compatible with concrete brick, tile, precast panels, pavers, and cast-in-place concrete surfaces, with coverage of 100–300 sq. ft. per gallon.

Fired Clay Brick, Tile, and Terra Cotta

Approved for use on fired clay brick, tile, unglazed terra cotta, and pavers, with coverage of 150–350 sq. ft. per gallon depending on surface porosity.

Exterior Building Facades — Water Repellent Protection

For contractors seeking a single-product solution that delivers both color and water repellency on exterior masonry facades, BMC II eliminates the need for a separate topcoat water repellent treatment.

Interior Masonry Walls

Suitable for interior masonry applications where no harsh odors, vapor permeability, and a clean flat finish are required.

Compatible Materials

• Architectural Concrete Block — Burnished, Smooth, Split-faced, Ribbed
• Concrete Brick
• Concrete Tile
• Precast Concrete Panels
• Concrete Pavers
• Cast-in-place Concrete
• Fired Clay Brick
• Fired Clay Tile
• Unglazed Terra Cotta
• Fired Clay Pavers

Product Documents

• Product Data Sheet
• Safety Data Sheet
• Safety Data Sheet (Spanish)
• SDS Canadian French
• VOC Compliance
• Product Test Data
• LEED Verification Letter
• SCS Certification

Application Instructions

Surface Preparation

1. Protect people, vehicles, property, metal, and all surfaces not designated for coating from product, residue, splash, fumes, and wind drift using drop cloths or other proven protective material.
2. Protect and/or divert foot and vehicle traffic from the work area.
3. Ensure surfaces are clean, dry, and absorbent before application.
4. Correct the causes of any moisture-related stains before application. Thoroughly clean efflorescence, algae, and other moisture-related stains.
5. In coastal areas, check for salt contamination and address prior to application. Contact PROSOCO Customer Care for cleaning recommendations.
6. Roughen or abrade glazed or glossy surfaces to ensure proper adhesion before application.

Priming (Optional)

1. BMC II requires no primer. If a priming coat is desired, use PROSOCO Siloxane WB diluted at one part product to 19 parts water.
2. Apply BMC II within 48 hours of primer application.

Temperature Requirements

1. Do not apply if air or surface temperatures are below 40°F (4°C), or if temperatures are expected to fall below 40°F within 24 hours of application.
2. Do not apply to surfaces hotter than 95°F (35°C).

Application

1. Apply BMC II using a roller, brush, or airless sprayer.
2. Refer to coverage rates by substrate type: Architectural Concrete Block 100–150 sq. ft./gal.; Concrete/Precast/Cast-in-place 100–300 sq. ft./gal.; Fired Clay Brick/Tile/Terra Cotta/Pavers 150–350 sq. ft./gal. Always test on a representative area first.

Storage and Handling

1. Keep product from freezing. Store in a cool, dry place at 45–100°F (7–38°C).
2. Always seal container after dispensing. Do not alter or mix with other chemicals.
3. Store containers upright and factory-sealed. Do not double stack pallets.
4. Dispose of unused product and container in accordance with local, state, and federal regulations.

Safety Data Summary

Hazard Information

• Flash point greater than 200°F (93°C) — low flammability risk under normal conditions.
• pH 9.0–10.0 — alkaline product; avoid contact with eyes and skin.
• Keep from freezing; freeze point is 32°F (0°C).
• 24-hour emergency information: INFOTRAC at 800-535-5053.

Safe Handling

• Always read the full label and Safety Data Sheet (SDS) for complete precautionary instructions before use.
• Use appropriate safety equipment and job-site controls during application and handling.
• Do not alter or mix with other chemicals.
• Dispose of unused product and container in accordance with local, state, and federal regulations.

Frequently Asked Questions

Q: Does BMC II require a primer before application?
A: No. BMC II needs no primer. However, if a priming coat is desired, PROSOCO Siloxane WB can be used at a dilution of one part product to 19 parts water, with BMC II applied within 48 hours of primer application.

Q: Can BMC II be custom tinted?
A: Yes. BMC II is compatible with the CCE ColorCast Ecotoner colorant system for predictable color matching. It is available in four bases — Pastel, Tint, Deep, and Accent — and can be custom tinted by local distributors. Note that the manufacturer does not endorse the use of organic colorants, as they may result in color fading.

Q: Is BMC II suitable for use on horizontal surfaces subject to foot or vehicle traffic?
A: No. BMC II is not intended for use on horizontal surfaces subject to vehicular or pedestrian traffic.

Q: Is BMC II compliant with VOC regulations in my state or district?
A: BMC II is compliant with all national, state, and district AIM VOC regulations. For confirmation of compliance with specific district or state regulations, refer to the VOC Compliance document linked in the Product Documents section.

Q: Is this product available for immediate shipment?
A: BMC II is a special order product. Production lead times may apply. Contact Diamond Tool Store for current lead time information before placing your order.