I've used this a number of times now and its complete rubbish. In context I have the lightest amount of mould on my decking, sprayed this twice, left it and it has done absolutely nothing. Granted in some random areas and it has removed some. In terms of expectations, I've used mpuld removal sprays indoors like Cillit Bang mould remover on black thick mould and its demolished it so my expectations were that an outdoor spray equivalent would have similar results. It hasnt, its rubbish, dont bother.