penetrative sealers for natural stones

Penetrative Sealers to Enhance Natural Stone Surfaces

Natural stones are a cornerstone of landscaping designs and architectural projects. They impart a sense of beauty and durability to outdoor spaces and interior environments. However, proper sealing is essential to ensure these stone surfaces maintain their allure. Additionally, they must endure the rigours of nature and everyday use. In this discussion, we’ll explore the benefits of using penetrative sealers for natural stone in landscaping, exteriors, and interiors.

“The environment is everything that isn’t me.”

Albert Einstein

Among the various sealing options available, penetrative sealers stand out for their ability to deeply protect the stone while preserving its natural aesthetics. We will delve into the intricacies of penetrating sealers and compare them with non-penetrating options. We will also explore solvent-based versus water-based sealers, and discuss sustainable application methods and vapour transmission.

Understanding penetrative sealers:

Penetrative or impregnating sealers penetrate the stone’s pores to create a robust barrier. Therefore, it effectively guards against stains, water damage, and other environmental hazards. Unlike surface sealants, which form a visible film atop the stone, impregnating sealers maintain the stone’s natural look and texture. At the same time, it provides enhanced protection.

Comparing Penetrative and Non-Penetrative (Superficial) Sealers:

Penetrative Sealers:Superficial Sealers:
Preserve natural aesthetics.Form a visible film on the surface.
Deeply penetrate stone pores for comprehensive protection.Alter the appearance of the stone, potentially enhancing colour but sacrificing the natural look.
Offer long-lasting protection.It may require more frequent reapplication.
Ideal for high-traffic areas and outdoor use.Suitable for specific aesthetic preferences but may not offer as robust protection.
Comparision between penetrative and superficial sealers.

Landscaping with Natural Stone:

Landscapers often use natural stone for various features such as patios, walkways, retaining walls, water bodies, and decorative elements. Outdoor areas endure relentless exposure to extreme weather, constant foot traffic, and natural debris. Penetrative sealers offer an ideal solution for protecting natural stone in landscaping settings because they can deeply penetrate the stone’s pores and provide long-lasting protection against stains, water damage, and weathering.

By applying an impregnating sealer to natural stone used in landscaping, such as limestone, sandstone, or granite, homeowners and landscapers can:

  1. Preserve the stone’s natural beauty: Penetrative sealers maintain its original colour, texture, and appearance, enhancing its aesthetic appeal and contributing to the overall landscape design.
  2. Enhance durability: The sealer forms a protective barrier within the stone, preventing water intrusion, freeze-thaw damage, efflorescence, and deterioration caused by exposure to UV radiation and environmental pollutants.
  3. Facilitate easier maintenance: Sealed natural stone surfaces pave the way for easier maintenance, reduce frequent resealing, and minimise costly repairs and replacements over time.

Penetrative sealing for Exterior Applications in Buildings:

Architects incorporate natural stone for exterior cladding, facades, walkways, and hardscape elements. These surfaces endure various environmental forces, from rain and humidity to temperature changes and pollution. Penetrative sealers offer unparalleled protection for exterior stone applications, ensuring longevity and preserving the building’s aesthetic appeal.

By applying penetrative sealers to natural stone exteriors, architects, builders, and homeowners can:

  1. Extend the stone’s lifespan: Penetrative sealers penetrate deeply into the stone substrate, providing durable protection against moisture ingress, efflorescence, mould growth, and salt damage. Thus, they prolong the lifespan of the building’s exterior.
  2. Maintain architectural integrity: Sealed natural stone surfaces retain their natural appearance and texture, enhancing the building’s architectural character and complementing its aesthetic.

Interior Applications in Buildings:

We use natural stone for flooring, countertops, wall cladding, and decorative accents in building interiors. These surfaces endure daily wear and tear, spills, and cleaning agents yet remain resilient in adversity. Penetrative sealers offer an effective solution for protecting interior stone surfaces, ensuring durability and maintaining aesthetic appeal.

By applying penetrative sealers to natural stone interiors, designers, homeowners, and facility managers can:

  1. Enhance stain resistance: Penetrative sealers impede the penetration of liquids and contaminants into the stone pores, reducing the likelihood of staining and etching caused by spills, oils, and acidic substances.
  2. Simplify cleaning and maintenance: Sealed natural stone surfaces look stunning, making cleaning and maintenance a breeze. With minimal effort and resources, you can keep them looking great and functioning well.
  3. Promote a healthier indoor environment: By preventing the growth of mould, mildew, and bacteria on sealed stone surfaces, penetrative sealers contribute to a cleaner, healthier indoor environment, particularly in areas prone to moisture and humidity.

Solvent-Based vs. Water-Based Sealers:

Solvent-based sealers:Water-based sealers:
Provide excellent penetration into dense stone types.Environmentally friendly with low VOC content.
Typically offer enhanced durability and longevity.Dry faster than solvent-based sealers.
May contain volatile organic compounds (VOCs), potentially harmful to health and the environment.Suitable for indoor applications and areas with strict VOC regulations.
Typical solvents include xylene, toluene, hexane and mineral oils.It may not penetrate as deeply as solvent-based counterparts, particularly in denser stone types.
Comparison between Solvent-based and Water-based sealants.

Vapour Transmission and Longevity:

One significant advantage of penetrative sealers is their ability to allow vapour transmission. While liquids may not penetrate the sealed surface, air can escape, allowing the stone to “breathe.” Thus, this characteristic helps prevent deterioration and ensures the longevity of the sealed surface.

Sustainable Application Methods:

To minimise environmental impact, consider sustainable application methods such as:

  • Low-pressure sprayers to reduce overspray and waste.
  • Use of eco-friendly applicators and cleaning tools.
  • Proper disposal of unused sealer and cleaning materials.

Colour Differences and Considerations:

We must consider potential colour changes when selecting a sealer. Penetrative sealers typically do not significantly alter the stone’s colour, maintaining its natural appearance. However, some water-based sealers may temporarily darken the stone until fully cured. Testing the sealer on a small, inconspicuous area before completing the application is crucial.

For your interest, we have linked a video showing the complete maintenance of natural stone surfaces by Finalit in Laxenburg, Austria. We have worked with Finalit in the past and found their approach and solution most sustainable. First of all, the surface needs to be thoroughly cleaned before using a sealer. It is your last chance to remove dirt and other pollutants like rust or graffiti before you commit the surface to impregnation.

Remember, all types of natural stones and surfaces that we have listed on our website need protection. There is no such thing as maintenance-free in the construction business. All surfaces, natural or engineered, need maintenance.

In summary, penetrative sealers enhance the beauty, durability, and longevity of natural stone surfaces used in landscaping and exterior and interior building applications. By investing in quality sealant products and following proper application techniques, homeowners, landscapers, architects, and designers can ensure that natural stone retains its allure and functionality for years to come, enriching outdoor environments and interior spaces.


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