Stonecare4U Slate Sealer Matt (dry) Finish is a high-performance product formulated for porous external natural surfaces, such as slate, terracotta, yorkstone, quarry tile, sandstone, limestone, concrete and many more stone types. Most noteworthy is that it provides excellent water repellency and long-lasting protection. Once sealed, the attractive matt finish helps to prevent efflorescence, moss and algae growth and creates a self-cleaning surface tension that reduces the need for regular maintenance. Firstly, this product is a professional-grade sealer that creates a matt looking finish. Secondly, the safe formula imparts excellent water repellency and stain resistance. It also has a technical formula that significantly reduces the capillary water absorption of the treated surface, but doesn’t clog the pores or capillaries. Significantly, this reduces the potential for organic soiling and moss and algae growth, whilst allowing the surface material the ability to “breathe” and transfer moisture vapour. Please Note: Slate Sealer Matt (dry) Finish may cause a change of colour on some surfaces – always try the product in an inconspicuous area prior to use. Surfaces that are not to be sealed should be protected with masking material. Clean sealed areas with a mild, ph neutral cleaner or a very low concentration of our outdoor cleaner range. Do not use harsh or abrasive cleaning agents as this can have a negative effect on the treated surface. NOT RECOMMENDED FOR USE ON HIGHLY POLISHED, CERAMIC/GLAZED, DENSE OR NON-POROUS SURFACES.