Sealing Clay Roof Tiles? 

Hydrofix can be used to seal your porous cement roof tiles to prevent further mould or algae from growing onto them. However, you must use Powafix Fungi Fix to kill the mould and algae from the roots. Once you have done so, ensure the tiles have been rinsed and are dry. Thereafter apply two coats of Hydrofix wet on wet. POWAFIX® suggests applying the product at a 8 m² at a time as the product dries quickly.

If after using Hydrofix water repellant on your surface you find a white substance / flake has appeared- this product has been applied to a non-porous substrate (ie; ceramic tiles) resulting in the water being evaporated, leaving behind the silicone from the product. Hydrofix must be applied to porous / dry substrates only.