Natural Stone Treatment WB Water Repellent

Sure Klean® Weather Seal Natural Stone Treatment WB — Penetrating Water Repellent for Limestone, Marble & Travertine

Sure Klean® Weather Seal Natural Stone Treatment WB is a water-based, penetrating water repellent formulated for limestone, marble, travertine, and most other traditional masonry surfaces. Designed for contractors and trades professionals working on both new construction and existing masonry, it delivers long-lasting water repellency without the odor, regulatory complications, or handling challenges associated with solvent-based products. The product is ready-to-use, VOC-compliant, and low-odor, making it suitable for interior and exterior applications alike.

Unlike conventional silane, siloxane, acrylic, or metallic stearate water repellents, Natural Stone Treatment WB is specifically modified for effectiveness on calcareous surfaces — a category where standard siloxane products routinely underperform. It also reduces the severity of biological staining from fungal growth, mold, and mildew, which is a persistent problem in high-humidity regions.

Technical Specifications

Key Features & Benefits

Effective on Calcareous Surfaces

Standard siloxane water repellents are not optimized for limestone, marble, and other calcareous substrates — surfaces that make up a significant share of natural stone facades and interiors. Natural Stone Treatment WB is specifically modified to penetrate and protect these materials, providing performance superior to common silane, siloxane, acrylic, or metallic stearate repellents. Contractors working on high-end stone finishes can rely on this product where general-purpose repellents fall short.

Water-Based Formula — Matches Solvent Performance Without the Drawbacks

This product delivers equivalent water-repellency performance to solvent-based treatments while eliminating the regulatory burden, odor concerns, and disposal complications that come with solvent systems. The VOC content is under 5 g/L, making it compliant with all national, state, and district AIM VOC regulations. This is a practical advantage on job sites with occupants present or in jurisdictions with strict air quality requirements.

Vapor-Permeable — Surfaces Continue to Breathe

Natural Stone Treatment WB does not form a surface film or trap moisture within the substrate. Treated surfaces remain vapor-permeable, which is critical for masonry that experiences thermal cycling or moisture migration from within. Trapping moisture behind a non-breathable coating can cause spalling and efflorescence — this product avoids that failure mode.

Biological Stain Resistance

In high-humidity climates, dark biological staining from mold, mildew, and fungal growth is a recurring maintenance problem on natural stone and masonry. Natural Stone Treatment WB reduces the severity of this staining, protecting both the appearance and integrity of treated surfaces between maintenance cycles.

Does Not Alter Appearance or Texture

The product will not form a surface film, add gloss, or change the substrate's color or texture. For contractors working on architecturally significant stone — where preserving the original finish is a specification requirement — this is a non-negotiable performance attribute. Always test in an inconspicuous area before full application to confirm desired results.

Protects Mortar, Grout Joints, and Hairline Cracks

Natural Stone Treatment WB also protects adjacent mortar and grout joints, and resists water penetration when applied over existing shrinkage cracks of 0.02 inches (0.5 mm) or less. This makes it useful across entire wall assemblies rather than stone faces alone, though it will not compensate for structural cracks, open joints, or material defects.

Common Applications

Natural Stone Facade Water Repellency

Apply to limestone, marble, and travertine exterior facades to provide long-lasting penetrating water repellency without altering the stone's appearance. Suitable for new construction or existing surfaces in need of protection.

Interior Natural Stone Surfaces

The low-odor, water-based formula makes Natural Stone Treatment WB appropriate for interior applications where ventilation is limited and occupant exposure is a concern. Apply to interior stone floors, walls, and features for water and stain resistance.

Traditional Masonry Water Repellency

Beyond natural stone, the product is effective on most traditional masonry surfaces, protecting mortar and grout joints as well as the masonry units themselves. Particularly valuable in high-humidity regions where biological staining is a persistent issue.

High-Humidity Climates — Biological Stain Control

In regions with elevated relative humidity, fungal growth, mold, and mildew staining on stone and masonry can accelerate. Natural Stone Treatment WB reduces the severity of this staining, extending the service interval between cleaning cycles.

Restoration and Preservation Projects

Because the product does not change surface color, gloss, or texture, it is well-suited to restoration work on historic or architecturally sensitive masonry where maintaining the original appearance is required.

Compatible Materials

• Limestone
• Marble
• Travertine
• Other calcareous masonry surfaces
• Traditional masonry (general)
• Mortar and grout joints (new or existing)

Limitations

• Biological staining must be removed prior to application
• May damage glass or be difficult to remove from glass — protect all glazing
• Not suitable for polished or glazed 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 applications
• Will not prevent water penetration through structural cracks, defects, or open joints
• Will not compensate for structural or material defects

Product Documents

• Product Data Sheet (English)
• Product Data Sheet (Canadian French)
• Product Data Sheet (Spanish)
• Safety Data Sheet (English)
• Safety Data Sheet (Spanish)
• Safety Data Sheet (Canadian French)
• VOC Compliance Documentation
• LEED Verification Letter
• Natural Stone Treatment WB Info Sheet

Application Instructions

Surface Preparation

1. Protect people, vehicles, property, plants, windows, painted surfaces, anodized aluminum, and all non-masonry surfaces from product contact, splash, spray, residue, fumes, and wind drift.
2. Protect and/or divert pedestrian and vehicle traffic as needed.
3. Test metal finishes and glass for potential damage prior to application; protect as necessary.
4. Ensure the surface is clean and free of dirt, dust, oils, and other contaminants. If necessary, clean with an appropriate PROSOCO surface preparation cleaner.
5. Remove all biological staining prior to application. PROSOCO recommends cleaning with ReKlaim followed by Limestone & Masonry Afterwash. Insufficient removal of biological staining can cause noticeable discoloration after treatment (though this typically disappears with weathering exposure).
6. Ensure all caulks and sealants are in place and thoroughly cured before application.
7. Cap and make watertight the tops of walls prior to application.
8. Surface must be thoroughly dry before application begins.

Temperature Requirements

1. Surface and air temperatures must be at least 50°F (10°C) and no higher than 90°F (32°C) during application.
2. If freezing conditions existed prior to application, allow masonry to fully thaw before proceeding.
3. Avoid application to surfaces in direct sunlight or exposed to high winds, as rapid drying can occur and compromise penetration. Keep surface temperature relatively cool.
4. Protect surfaces from direct sunlight for several hours prior to beginning application. When possible, begin application on shaded surfaces. On warm days, apply early in the day.

General Application Guidance

1. Product is ready-to-use — no dilution required.
2. Avoid breathing mist during application. Avoid exposing building occupants to spray.
3. When applying indoors, provide adequate cross ventilation.
4. Always test in an inconspicuous area to ensure desired results before proceeding with overall application.

Safety Data Summary

Hazard Information

• pH 12.9 — strongly alkaline; may be irritating to skin, eyes, and mucous membranes
• Flash point greater than 212°F (>100°C) — not flammable under standard conditions
• Freeze point 32°F (0°C) — do not allow product to freeze
• May damage glass and certain metal finishes upon contact
• Avoid breathing mist or spray
• 24-Hour Emergency Information: INFOTRAC at 800-535-5053

Personal Protective Equipment

• Read the full label and Safety Data Sheet before use
• Use appropriate safety equipment as specified in the SDS
• Implement appropriate job site controls during application and handling

Safe Handling

• Protect all non-masonry surfaces, glass, painted surfaces, and anodized aluminum from contact
• Do not allow product to freeze during storage or transport
• Store in a tightly sealed, unopened container; shelf life is 2 years under these conditions
• Provide adequate cross ventilation for interior applications
• Avoid exposing building occupants to spray or mist

Frequently Asked Questions

Q: Why use Natural Stone Treatment WB instead of a standard siloxane water repellent on limestone or marble?
A: Standard siloxane repellents are not optimized for calcareous surfaces such as limestone, marble, and travertine. Natural Stone Treatment WB is specifically modified for effectiveness on these substrates and provides water-repellent protection superior to common silane, siloxane, acrylic, or metallic stearate products on these materials.

Q: Will this product change the appearance of the stone?
A: No. Natural Stone Treatment WB will not form a surface film, add gloss, or alter the color or texture of the substrate. Always test in an inconspicuous area before full application to confirm results on your specific stone.

Q: Can this product be used on polished marble or glazed surfaces?
A: No. The product is not suitable for polished or glazed surfaces. It is designed for natural, unpolished masonry and stone substrates.

Q: Is the surface still vapor-permeable after treatment?
A: Yes. Treated surfaces continue to breathe — the product does not trap moisture or form a surface film. This is important for masonry assemblies where vapor drive from the interior or thermal cycling could otherwise cause issues with a non-permeable coating.

Q: Will this product stop water through structural cracks or open joints?
A: No. Natural Stone Treatment WB resists water penetration through existing shrinkage cracks of 0.02 inches (0.5 mm) or less, but it will not prevent water penetration through structural cracks, defects, or open joints. All caulking, sealants, and wall cap conditions must be addressed before application.

Q: Does biological staining need to be removed before applying this product?
A: Yes. Existing biological staining must be removed prior to application. Insufficient cleaning can result in noticeable discoloration after treatment. PROSOCO recommends cleaning with ReKlaim followed by Limestone & Masonry Afterwash before applying Natural Stone Treatment WB.