Product Description
PROSOCO BMC II Tint Base — Breathable Masonry Water Repellent Color Coating
PROSOCO Breathable Masonry Coating II (BMC II) Tint Base is a silicone emulsion-based water repellent color coating engineered for professional application on masonry substrates. It combines the aesthetic finish of a high-quality paint with the protective performance of a breathable water repellent, allowing water vapor to escape while blocking destructive liquid water infiltration. This 5-gallon unit is formulated for contractors working on both historic restoration and new construction masonry projects.
Unlike conventional paints, BMC II's unique silicone emulsion formulation delivers superior resistance to UV degradation, moisture intrusion, and soiling — extending service life beyond what standard coatings can offer. Its field-proven technology has been used on landmark structures including the U.S. Capitol and numerous other historic and contemporary buildings across the United States and Europe.
Technical Specifications
| Specification | Details |
|---|---|
| Product Line | BMC II (Breathable Masonry Coating II) |
| Base Type | Tint Base |
| Form | White viscous batter-like liquid with mild odor |
| Size | 5 Gallon |
| Technology | Silicone emulsion formulation |
| Specific Gravity | 1.38 (Tint Base) |
| Weight per Gallon | 11.55 lbs (Tint Base) |
| Percent Solids by Weight | 55% (Tint Base) |
| Percent Solids by Volume | 38% (Tint Base) |
| VOC Content | 100 g/L maximum |
| VOC Compliance | Compliant with all national, state, and district AIM VOC regulations |
| Vapor Permeability | Highly vapor permeable |
| ASTM Compliance | Meets and exceeds requirements of ASTM E 2357 |
| Finish | Attractive flat finish |
| Flash Point | >200°F (>93°C) per ASTM D 3278 |
| Freeze Point | 32°F (0°C) |
| pH | 9.0–10.0 |
| Shelf Life | 1 year in tightly sealed, unopened container |
| Storage Temperature | 45–100°F (7–38°C) |
| Application Temperature | 40°F (4°C) minimum air/surface; 95°F (35°C) maximum surface |
| Colorant Compatibility | Compatible with CCE ColorCast Ecotoner colorant system |
| Special Order | Yes — production lead times may apply |
Key Features & Benefits
Breathable Water Repellent Protection
BMC II is highly vapor permeable, allowing moisture trapped within the masonry to escape as vapor while preventing liquid water from penetrating the surface. This dual action preserves masonry integrity and prevents moisture-related deterioration such as spalling, efflorescence, and freeze-thaw damage.
Silicone Emulsion Formulation
The silicone emulsion base provides enhanced resistance to UV degradation, moisture intrusion, and surface soiling compared to most conventional paints. This translates to a more durable, longer-lasting coating that reduces the frequency of recoating on demanding job sites.
Excellent UV Stability and Color Retention
BMC II delivers exceptional color retention and UV stability, maintaining appearance over time even on exterior surfaces exposed to direct sunlight. Contractors can specify it with confidence for both interior and exterior applications without concern for rapid color fade.
No Primer Required
BMC II needs no primer coat, streamlining application and reducing material costs on the job. 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 primer application.
Broad Application Method Compatibility
The coating can be applied with a roller, brush, or airless sprayer, giving crews flexibility to match application equipment to the job condition. No specialized equipment is required beyond what most masonry painting crews already carry.
Custom Tintable with CCE ColorCast Ecotoner System
BMC II Tint Base is compatible with the CCE ColorCast Ecotoner colorant system for predictable, consistent color matching. Local distributors can custom tint bases, and BMC II is available in four bases — Pastel, Tint, Deep, and Accent — to achieve the widest possible color range.
Common Applications
Historic Building Restoration
BMC II has a documented track record on historic structures including the U.S. Capitol, making it a trusted choice for restoration work where performance and appearance standards are stringent.
Architectural Concrete Block
Suitable for burnished, smooth, split-faced, and ribbed architectural concrete block surfaces, with coverage of 100–150 sq. ft. per gallon.
Concrete, Precast, and Pavers
Compatible with cast-in-place concrete, precast panels, concrete brick, tile, and pavers, with coverage ranging from 100–300 sq. ft. per gallon depending on surface porosity.
Fired Clay Masonry
Suitable for fired clay brick, tile, unglazed terra cotta, and pavers, with coverage of 150–350 sq. ft. per gallon.
Exterior Masonry Façades
Designed for exterior masonry walls where both color and water repellency are required, protecting façades from destructive liquid water infiltration while preserving appearance.
Interior Masonry Surfaces
Equally suitable for interior masonry applications, with no harsh odors during or after application making it appropriate for occupied or partially occupied spaces.
Compatible Materials
- Architectural concrete block (burnished, smooth, split-faced, ribbed)
- Cast-in-place concrete
- Concrete brick
- Concrete tile
- Precast panels
- Concrete pavers
- Fired clay brick
- Fired clay tile
- Unglazed terra cotta
- Fired clay pavers
- Marble, travertine, and limestone (refer to datasheet for full coverage data)
Limitations
- Not for use on horizontal surfaces subject to vehicular or pedestrian traffic.
- Not suitable for application on some resin paints.
- Manufacturer does not endorse use of organic colorants; use of organic colorants for color matching may result in color fading.
- Do not apply if temperatures are below 40°F (4°C) or expected to drop below 40°F within 24 hours.
- Do not apply to surfaces hotter than 95°F (35°C).
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
- Protect all people, vehicles, property, metal, and surfaces not intended for coating from product, residue, splash, fumes, and wind drift using drop cloths or other proven protective material.
- Ensure surfaces are clean, dry, and absorbent before application.
- Correct all causes of moisture-related staining prior to application.
- Thoroughly clean efflorescence, algae, and other moisture-related stains from the surface.
- In coastal areas, check for salt contamination and address before coating.
- Roughen or abrade any glazed or glossy surfaces to ensure proper adhesion.
Priming (Optional)
- BMC II requires no primer; however, a priming coat may be applied if desired.
- Use PROSOCO Siloxane WB at a dilution ratio of one part product to 19 parts water as a primer.
- Apply BMC II within 48 hours of primer application.
Application
- Confirm air and surface temperatures are between 40°F (4°C) and 95°F (35°C), and that temperatures will not drop below 40°F within 24 hours of application.
- Apply BMC II using a roller, brush, or airless sprayer.
- Apply evenly across the masonry surface according to coverage rates for the specific substrate type.
Storage & Handling
- Keep product from freezing. Store in a cool, dry place.
- Maintain storage temperature between 45–100°F (7–38°C).
- Always seal container tightly after dispensing.
- Do not alter or mix with other chemicals.
- Do not double stack pallets.
- Dispose of unused product and container in accordance with local, state, and federal regulations.
Safety Data Summary
Safe Handling
- Always read the full label and Safety Data Sheet (SDS) before use.
- Use appropriate safety equipment and job-site controls during application and handling.
- Keep product from freezing during storage and transport.
- Do not alter or mix with other chemicals.
- 24-Hour Emergency Information: INFOTRAC at 800-535-5053.
Frequently Asked Questions
Q: Is BMC II Tint Base a stock item or special order?
A: BMC II is a special order product. Production lead times may apply — plan orders in advance to avoid project delays.
Q: Does BMC II require a primer before application?
A: No primer is required. However, an optional priming coat using PROSOCO Siloxane WB diluted 1:19 with water may be applied, with BMC II applied within 48 hours of primer.
Q: Can BMC II Tint Base be custom tinted on site?
A: BMC II is compatible with the CCE ColorCast Ecotoner colorant system for predictable color matching. Custom tinting can be performed by local distributors. Note that the manufacturer does not endorse organic colorants, as they may cause color fading.
Q: What application equipment is compatible with BMC II?
A: BMC II can be applied with a roller, brush, or airless sprayer. No specialized equipment beyond standard masonry coating tools is required.
Q: Is BMC II suitable for both interior and exterior use?
A: Yes. BMC II is ideal for both interior and exterior masonry surfaces and produces no harsh odors, making it appropriate for a wide range of project conditions.
Q: What is the shelf life of BMC II?
A: BMC II has a shelf life of 1 year in a tightly sealed, unopened container stored upright in a cool, dry place at 45–100°F (7–38°C).


