Bare concrete must be porous for sealer to adhere, therefor it is recommended bare concrete be treated with a Hydrochloric Acid solution, 1 part to 10 parts water for a smooth steel trowelled finish and 1 part to 20 parts water for a rough stipple finished concrete. If the concrete is powdery or soft do not acid wash as this may damage the surface.The first coat of sealer should be diluted with Thinners and mixed well before application to aid the penetration of the sealer into the surface, 20% on smooth steel trowelled concrete and 10% on a rough stipple trowelled concrete. Apply sealer to a dry surface at the spread rate of 4 square metres per litre per coat. It is important to apply at this spread rate to allow the sealer to penetrate into the surface. Allow a minimum of two hours between coats. Do not apply in hot direct sun or temperatures above 27 degees as bubbling or adhesion problems may occur.