Natural Stone Treatment Water Repellent - Bulk

Natural Stone Treatment – Long-Lasting Water Repellent for Limestone, Marble & Calcareous Masonry

Natural Stone Treatment is a modified siloxane water repellent engineered for limestone, marble, and most other traditional masonry and calcareous surfaces. It penetrates deeply at the molecular level to deliver long-lasting water repellent protection on both interior and exterior applications without altering the natural appearance of the substrate. This product is specifically formulated for professional contractors working with stone and masonry assemblies where appearance preservation and moisture management are critical.

Unlike conventional silane or siloxane water repellents, Natural Stone Treatment is modified specifically for effectiveness on calcareous surfaces where standard products typically underperform. It provides water repellent protection superior to common silane, siloxane, acrylic, or metallic stearate water repellents, and also reduces the severity of biological staining common in high-humidity environments by resisting fungal growth, mold, and mildew.

Technical Specifications

Key Features & Benefits

Deep Molecular Penetration

The small molecular size of Natural Stone Treatment allows it to penetrate deeply into the substrate rather than sitting on the surface. This deep penetration delivers protection that is more durable and longer-lasting than surface-applied coatings, which is critical on high-traffic or exposed exterior masonry.

Breathable – Does Not Trap Moisture

Treated surfaces remain vapor-permeable, allowing moisture within the substrate to escape. Contractors working on existing or occupied structures benefit from this breathability because it prevents the trapped-moisture issues that can lead to spalling, delamination, or efflorescence over time.

Invisible Finish – No Film, No Gloss

Natural Stone Treatment does not form a surface film or gloss, preserving the natural appearance of the masonry. This is especially important on architectural limestone and marble facades where owners and specifiers require no change in aesthetics.

Alkali-Resistant Formula

The product is formulated to resist alkali degradation, which means it protects both new and existing mortar and grout joints in addition to the stone face itself. This extends the effective service life of the treatment across the full assembly.

Biological Stain Resistance

Natural Stone Treatment reduces the severity of biological staining common in regions with high relative humidity. Treated surfaces resist dark staining and degradation caused by fungal growth, mold, and mildew, reducing long-term maintenance requirements.

Saltwater and Atmospheric Soiling Resistance

The product resists damage from saltwater pools and reduces atmospheric soiling on treated surfaces. These properties make it well suited for coastal projects, pool surrounds, and urban facades exposed to airborne contaminants.

Crack Bridging on Fine Shrinkage Cracks

Natural Stone Treatment resists water penetration when applied over existing shrinkage cracks of 0.02 inches or less. This provides an added layer of protection on substrates that show normal minor cracking without requiring crack repair prior to application.

Common Applications

Limestone Facades and Cladding

Natural Stone Treatment is specifically modified for calcareous surfaces like limestone, where conventional siloxane products are less effective. It delivers deep penetrating protection on architectural limestone panels and curtain walls.

Marble Surfaces – Interior and Exterior

Suitable for marble in both interior and exterior settings, the product protects against water ingress and biological staining without altering the stone's appearance or creating a surface film.

Traditional Masonry Assemblies

The alkali-resistant formulation makes it appropriate for full masonry wall systems including mortar and grout joints, protecting the complete assembly rather than the stone face alone.

Pool Surrounds and Saltwater Environments

The product's resistance to saltwater pool chemistry makes it suitable for natural stone used in pool decks and surrounding masonry structures.

High-Humidity Exterior Environments

In regions with high relative humidity where biological staining is common, Natural Stone Treatment's resistance to mold, mildew, and fungal growth helps extend the clean appearance of treated masonry.

Urban and High-Traffic Facades

By reducing atmospheric soiling on treated surfaces, the product is practical for exterior masonry in urban environments where airborne pollution accelerates surface degradation and soiling.

Compatible Materials

• Limestone
• Marble
• Calcareous masonry surfaces
• Traditional masonry (general)
• Mortar and grout joints (new or existing)
• Concrete (per ASTM D 6532 test data)
• Brick (per ASTM C 67 test data)
• Concrete masonry units – CMU (per ASTM C 140 test data)

Limitations

• May damage glass or be difficult to remove – always protect glass surfaces
• Not appropriate for asphaltic or painted surfaces
• Not suitable for synthetic resin paints, gypsum, plaster, or other non-masonry surfaces
• Not recommended for below-grade application
• Will not prevent water penetration through structural cracks, open joints, or material defects
• May react with asphaltic crack-suppression membranes beneath stone, tile, grout, or paver surfaces – always pretest
• PROSOCO Strippable Masking is not appropriate for use with this product

Product Documents

• Product Data Sheet
• Safety Data Sheet
• Safety Data Sheet (Spanish)
• SDS Canadian French
• VOC Compliance

Application Instructions

Surface Preparation

1. Protect people, vehicles, property, plants, windows, painted surfaces, anodized aluminum, and all non-masonry surfaces from product, splash, spray, residue, fumes, and wind drift.
2. Ensure the surface is clean and free of dirt, dust, oils, and other contaminants. Use an appropriate PROSOCO surface preparation cleaner if necessary.
3. Surface must be thoroughly dry before application.
4. Ensure all caulks and sealants are in place and thoroughly cured prior to application.
5. The top of walls should be capped and made watertight prior to application.
6. Fill all cracks and voids to prevent penetration of fumes into the building when applying to occupied structures.
7. Pretest on any substrate that may incorporate asphaltic or crack-suppression membranes beneath the surface to ensure desired results.

Environmental Conditions

1. Apply when surface and air temperatures are between 40–90°F (4–35°C) for maximum effectiveness.
2. Avoid application on windy days, which can cause rapid evaporation of the solvent carrier.
3. Ensure fresh air entry and cross ventilation during application and drying.
4. Extinguish all flames, pilot lights, and other potential ignition sources during use and until all vapors have dissipated.
5. When applying to exteriors of occupied buildings, cover all windows, exterior intakes, and air conditioning vents, and shut down air handling equipment during application and until vapors have dissipated.

Safety Data Summary

Hazard Information

• Flammable liquid and vapor (Category 3)
• Aspiration hazard (Category 1) – may be fatal if swallowed and enters airways
• Causes mild skin irritation; may be harmful in contact with skin
• Flash point: 110°F (43°C)
• UN Number: UN1866
• 24-Hour Emergency: INFOTRAC 800-535-5053

Personal Protective Equipment

• Wear protective gloves
• Wear protective clothing
• Wear eye protection
• Wear face protection
• Use explosion-proof electrical, ventilating, and lighting equipment
• Use only non-sparking tools
• Take precautionary measures against static discharge

Safe Handling

• Keep away from heat, sparks, open flames, and hot surfaces – no smoking
• Keep container tightly closed
• Ground and bond container and receiving equipment
• Store in a well-ventilated place; keep cool; store locked up
• Ensure fresh air entry and cross ventilation during application and drying
• In case of skin contact: remove contaminated clothing and rinse skin with water
• If swallowed: call a poison center or physician immediately – do NOT induce vomiting
• In case of fire: use CO2, dry chemical, or foam for extinction
• Dispose of contents and container at an approved waste disposal facility

Frequently Asked Questions

Q: Why is Natural Stone Treatment preferred over standard silane or siloxane water repellents on limestone and marble?
A: Limestone and marble are calcareous surfaces that conventional silane and siloxane products are not optimized for. Natural Stone Treatment is specifically modified for effectiveness on calcareous masonry, and the datasheet states it provides superior water repellent protection compared to common silane, siloxane, acrylic, or metallic stearate alternatives.

Q: Will Natural Stone Treatment change the look of the stone after application?
A: No. The product does not form a surface film or gloss and does not alter the natural appearance of the substrate. Treated surfaces look the same as untreated surfaces.

Q: Can this product be used on interior surfaces as well as exterior?
A: Yes. Natural Stone Treatment is suitable for both interior and exterior surfaces. When applying indoors, good cross ventilation must be provided and all cracks and voids should be filled to prevent fume penetration into the building.

Q: Will the treatment prevent moisture from being trapped in the wall assembly?
A: Treated surfaces remain breathable and vapor-permeable. The product does not trap moisture within the substrate, which helps avoid issues such as spalling or efflorescence caused by vapor pressure buildup.

Q: What is the coverage rate?
A: Coverage ranges from 50 to 300 sq ft per gallon depending on the substrate. Refer to the Product Data Sheet for substrate-specific coverage guidance.

Q: Are there surfaces where this product should not be used?
A: Yes. Natural Stone Treatment should not be applied to asphaltic or painted surfaces, synthetic resin paints, gypsum, plaster, or other non-masonry surfaces. It is also not recommended for below-grade applications and will not seal structural cracks, open joints, or material defects.