Why is my outside sandstone / concrete / limestone getting mouldy, and how can I remove the mould?
Even when stone is sealed mould and algae can form over time, generally in areas where water is pooling, or in areas that do not receive regular sunshine. Once the stone had the mould and algae removed, a high quality penetrating Stain-Guarding treatment should be applied to reduce moisture penetration. At this point a regular bio-cide application (slow release mould killing product) can be applied as required to control mould. These products can be applied by Slique, and there are some very good off-the-shelf products that you or your landscapers can use.
