Sandstone is a natural rock formation, quarried and cut into smaller pieces. Homeowners and masons choose sandstone for patios, walkways, chimneys or foundations because it is durable. Sandstone is most recognisable as a New England dry wall, which is pieces of stone fit together and built without mortar. Depending on the region, sandstone is available in a wide range of colours including black, brown, red or grey. Each piece of sandstone will vary in colour, adding interest to the structure.
Mix equal parts chlorine bleach and water in a spray bottle.
Spray the mixture onto the mould generously and allow the bleach to remain on the surface for 10 to 15 minutes. Spray the mould a second time.
Scrub the mould with a stiff-bristled scrub brush. Rinse the area thoroughly with plain water. Repeat if necessary.
Spray a commercially prepared antimicrobial spray onto the mouldy surface. If the area is large or there are areas that are not reachable, rent a fogger. To use a fogger, place it in the area that has mould growth, add the antimicrobial agent and release the fogger. The mist will settle onto the mould and kill it.
Allow the spray to remain on the surface and dry completely. The spray will form an airtight protective coating and suffocate the mould.
Soak a rag with the antimicrobial spray and scrub the surface to remove mould.
Wear rubber gloves, safety goggles and a mould and particle respirator. Always wet mould before scrubbing to keep mould spores from releasing into the environment. Repair water leaks to keep areas free of mould.