PROSOCO BMC II Deep Base - Water Repellent Color Coating

PROSOCO BMC II Deep Base – Breathable Masonry Water Repellent Color Coating

PROSOCO Breathable Masonry Coating II (BMC II) Deep Base 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 both interior and exterior masonry applications. BMC II allows water vapor to escape from the substrate while blocking liquid water intrusion, preserving the masonry's appearance and extending its service life. This product is intended for use by contractors and restoration professionals working on architectural concrete block, brick, precast panels, tile, terra cotta, and similar masonry surfaces.

Unlike conventional paints, BMC II's unique silicone emulsion formulation delivers superior resistance to UV degradation, moisture, and soiling, resulting in a more durable and longer-lasting coating. It is highly vapor permeable, meets and exceeds ASTM E 2357 requirements, and requires no primer for standard applications. Its field-proven technology has been used on the U.S. Capitol and numerous historic and contemporary buildings throughout the United States and Europe.

Technical Specifications

Key Features & Benefits

Highly Vapor Permeable

BMC II is specifically engineered to allow water vapor to escape from masonry while blocking liquid water intrusion. For contractors working on existing masonry structures, this breathability prevents moisture from becoming trapped behind the coating, which can cause delamination, spalling, and efflorescence over time.

Silicone Emulsion Formula for Durability

The silicone emulsion formulation makes BMC II more resistant to UV degradation, moisture, and soiling than most conventional paints. Contractors can expect a more durable, longer-lasting result that reduces callback frequency and maintenance costs for building owners.

No Primer Required

BMC II adheres directly to properly prepared masonry surfaces without a primer coat, streamlining the application process and reducing material costs. An optional PROSOCO Siloxane WB primer coat (1 part product to 19 parts water) may be applied if desired, with BMC II applied within 48 hours.

Flexible Application Methods

The coating can be applied by roller, brush, or airless sprayer, giving crews the flexibility to choose the most efficient method for each job site condition. This versatility supports both large-surface production spraying and detailed brushwork on complex or textured masonry.

Excellent UV Stability and Color Retention

BMC II delivers excellent UV stability and exceptional color retention, ensuring that tinted finishes maintain their appearance over time. It is compatible with the CCE ColorCast Ecotoner colorant system for predictable, consistent color matching across projects.

VOC Compliant — Interior and Exterior Use

BMC II is compliant with all national, state, and district AIM VOC regulations and produces no harsh odors, making it appropriate for both interior and exterior applications. Contractors can use this product on regulated job sites without needing to source alternative low-VOC coatings.

Field-Proven on Landmark Structures

BMC II has been used on the U.S. Capitol and many other historic and contemporary buildings throughout the United States and Europe. This track record gives specifiers and contractors confidence in its long-term performance on demanding restoration and new construction projects.

Common Applications

Historic Masonry Restoration

BMC II's breathable, vapor-permeable formula makes it well suited for restoration work on historic masonry buildings where trapping moisture behind a coating would be damaging. Its field use on the U.S. Capitol and other landmark structures confirms its suitability for high-profile restoration projects.

Architectural Concrete Block Coating

BMC II can be applied to burnished, smooth, split-faced, and ribbed architectural concrete block at coverages of 100–150 sq. ft. per gallon. It provides color, water repellency, and protection on commercial and institutional masonry facades.

Brick and Fired Clay Surfaces

The coating is approved for use on fired clay brick, tile, terra cotta (unglazed), and pavers, with coverages ranging from 150–350 sq. ft. per gallon depending on surface texture and absorption. It preserves the appearance of brick while adding water repellent protection.

Precast Concrete Panels and Cast-in-Place Concrete

BMC II is suitable for precast panels and cast-in-place concrete surfaces, offering contractors a single coating solution that delivers color and water repellency on a wide range of structural concrete assemblies.

Exterior Facade Waterproofing and Color Coating

For new construction and renovation projects requiring both aesthetic finish and water protection on exterior masonry, BMC II eliminates the need for a separate waterproofing step, combining both functions in a single product.

Interior Masonry Coating

BMC II is rated for interior use and produces no harsh odors, making it appropriate for occupied or partially occupied structures where ventilation may be limited during application.

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
• Terra cotta (unglazed)
• 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 set for coating from product, residue, splash, fumes, and wind drift using drop cloths or other proven protective materials.
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 prior to coating. Thoroughly clean efflorescence, algae, and other moisture-related stains.
5. In coastal areas, check for salt contamination and address prior to application.
6. Roughen or abrade any glazed or glossy surfaces to ensure proper adhesion.

Priming (Optional)

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

Temperature and Conditions

1. Do not apply if air or surface temperatures are below 40°F (4°C), or if temperatures are expected to drop 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. Always test on a representative area of the actual substrate before full application to confirm coverage rate and appearance.
3. Refer to the coverage table for expected sq. ft. per gallon by substrate type.

Storage and Handling

1. Keep product from freezing. Store in a cool, dry place.
2. Maintain storage temperature between 45–100°F (7–38°C).
3. Always seal the container after dispensing. Do not alter or mix with other chemicals.
4. Do not double stack pallets.
5. Dispose of unused product and empty containers 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
• Freeze point 32°F (0°C) — do not allow product to freeze
• pH 9.0–10.0 — alkaline; avoid contact with eyes and prolonged skin contact
• 24-Hour Emergency Information: INFOTRAC at 800-535-5053

Safe Handling

• Always read the full label and Safety Data Sheet before use
• Use appropriate safety equipment and job-site controls during application and handling
• Keep from freezing during storage and transport
• Do not alter or mix with other chemicals
• Dispose of unused product and containers in accordance with local, state, and federal regulations

Frequently Asked Questions

Q: Does BMC II Deep Base require a primer before application?
A: No. BMC II needs no primer for standard masonry applications. An optional priming coat using PROSOCO Siloxane WB (diluted 1:19 with water) may be applied if desired, with BMC II applied within 48 hours of the primer coat.

Q: Can BMC II be used 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 available in custom colors?
A: Yes. BMC II is compatible with the CCE ColorCast Ecotoner colorant system and is available in four bases — Pastel, Tint, Deep, and Accent — allowing for the greatest range of colors. Local distributors can custom tint the product. Note that the manufacturer does not endorse the use of organic colorants, as they may result in color fading.

Q: Is BMC II a special order product?
A: Yes. BMC II is a special order product and production lead times may apply. Contact Diamond Tool Store for ordering details.

Q: What is the shelf life of BMC II?
A: BMC II has a shelf life of one year in a tightly sealed, unopened container stored upright in a dry place at 45–100°F (7–38°C).

Q: Can BMC II be applied over resin paints?
A: BMC II is not suitable for application on some resin paints. Always test on a representative area of the actual substrate prior to full application.