Slate Sealer Colour Boost is a high-performance stone sealer formulated especially for natural slate surfaces. It is also suitable for other porous natural stones such as sandstone (*exceptions apply) and limestone. Our powerful, yet eco-friendly sealer offers high-quality stain protection whilst the Colour Boost formula delicately enhances natural colours & appearance. It can be applied to external or internal surfaces. Sealed areas can be cleaned 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. This product is not recommended for use on non-porous surfaces. For application, ensure the slate is clean of loose debris and completely dry - allow at least 72 hours of dry weather. Ideal application temperatures are between 15°C and 23°C. Protect yourself with gloves, eyewear, a face mask, and appropriate clothing. Apply the first coat using a low-pressure sprayer, roller, natural-fibre brush, or sponge. Do not dilute the product! Remove excess sealer within 20-30 minutes. For best results, apply a second coat 45-60 minutes later. Keep the surface dry during the 72-hour curing process to avoid unsightly white patches. This sealer will alter the stone's colour, so test it in an inconspicuous area first. Mask any surfaces you don't want sealed. This product is not suitable for Kandla Grey (mid & light grey) sandstone.