Stone Sealer

GK Invisible Stone Sealer is our professional-grade waterproof stone sealer, developed specifically to penetrate and protect natural stone, concrete, and paving from both moisture ingress and staining. It delivers a completely transparent, breathable seal that guards the surface without altering its colour or appearance so the stone looks exactly as it should, simply sealed and protected from within.

Why Breathability Matters in a Stone Waterproofing Sealer

One of the most important, and most frequently overlooked, characteristics of a good stone waterproofing sealer is breathability. Many film-forming sealants create a surface-level barrier that prevents moisture from entering, but also prevents moisture vapour from escaping. On outdoor natural stone, this can trap moisture beneath the sealed surface, causing efflorescence, surface spalling, and in frost conditions, ice crystal expansion that damages the stone itself.

GK Invisible Stone Sealer works differently. Developed using short-chain per-fluorinated polymer technology, it penetrates into the stone's pore structure and seals from within, rather than coating from above. This creates a waterproof, breathable barrier where water is repelled from the surface, but moisture vapour can still travel upward through the stone and evaporate naturally.

For newly laid patios in particular, this breathability is essential: it allows residual moisture from the sub-base to continue escaping while preventing water ingress from above. This is what makes it the best stone waterproofer for outdoor natural stone in conditions like the UK, where freeze-thaw cycles and persistent damp are genuine threats to unprotected paving.

What GK Invisible Stone Sealer Protects Against

The protection delivered by this waterproof sealant for stone goes well beyond repelling rainwater. Once applied, the sealed surface resists all of the following:

• Water and moisture ingress: preventing the absorption and freeze-thaw damage that degrades unsealed stone over time
• Oil and grease: including cooking oils from barbecues, engine oil on driveways, and food fats on outdoor dining areas
• Food and beverage staining: the sealer is tested against ketchup, mustard, tea, coffee, and wine, making it a practical choice for kitchen terraces, al fresco dining spaces, and hospitality settings
• Algae, moss, and biological growth: the sealed surface restricts the establishment of organic growth that would otherwise penetrate and stain unsealed stone
• Dirt and grime pickup: sealed surfaces are significantly easier to maintain clean, as contaminants sit on the surface rather than absorbing into the stone

This comprehensive stain and moisture resistance makes it suitable for everything from a residential patio to a commercial outdoor dining area.

Stone Waterproofing for Every Natural Stone Surface

GK Invisible Stone Sealer is suitable for all natural stone and porous mineral surfaces, including:

• Indian sandstone, limestone, and slate paving: highly porous stones that benefit most from early sealing
• Granite: including honed and polished finishes that are sensitive to some sealing products. This formula is safe on honed granite and will not alter its finish.
• Marble: suitable for both indoor and outdoor marble surfaces
• Polished and exposed concrete: indoor polished concrete floors and outdoor concrete paving
• Block paving: protecting jointing sand and the paving surface from staining and biological growth
• Internal stone floors: suitable for kitchen floors, hallways, and bathrooms as well as external applications

One important limitation: GK Invisible Stone Sealer requires a porous, absorbent surface to work. It cannot be applied over painted surfaces, non-porous materials, or surfaces previously treated with silicone sealants. Always test a small inconspicuous area before full application, and ensure the surface is clean, completely dry, and free from algae, mould, or staining before treating.

Application: Clear Waterproof Coating for Stone, Correctly Applied

GK Invisible Stone Sealer is ready to use straight from the bottle with no dilution required. Apply generously and evenly with a brush, long-pile roller, or low-pressure sprayer to saturation point.

For porous stone, two to three wet-on-wet coats are recommended: the second and third coats must be applied while the previous coat is still wet to achieve deep penetration. Do not allow the surface to dry between coats. Remove any excess product with a clean microfibre cloth to prevent patching.

One 3-litre bottle covers up to 40 square metres on less porous surfaces, highly porous stone will require more product. Application temperature should be between 10°C and 30°C, and rain should not be expected within four hours of application.

For advice on surface preparation, choosing the right pre-treatment for algae or black spot before sealing, or any questions about application on a specific stone type, contact our team on 07557 111 297 or email sales@gkproductsuk.com. Free delivery on orders over £60 to mainland England, Wales and parts of Scotland.