Concrete surfaces such as pathways are porous even if they have been sealed. Because they are flat, horizontal surfaces, water often remains on them after rains. In areas of shade, the water takes longer to evaporate and leads to the growth of mould. While mould on pathways is not harmful, it is not attractive. Removing mould from concrete paths requires only basic household cleaning supplies and a bit of scrubbing to accomplish.
Fill a bucket with a mixture of four parts of water and one part of bleach.
Pour the mixture onto the concrete path, concentrating it on the areas where visible mould is growing. Allow the mixture to sit for five to 10 minutes to begin killing the mould.
Scrub the surface of the concrete path with a long-handled scrub brush. Use firm pressure and continue scrubbing until all traces of the mould is removed from the path.
Rinse the path off with a garden hose that has a sprayer attached to the end. Direct the water runoff away from desirable plants since the bleach may harm them.
Refill the bucket with one gallon of water and one to two tbsp of dish soap. Insert the scrub brush into the bucket and scrub the surface of the concrete path to remove the remaining bleach residue.
Rinse the path again with the garden hose to remove the soap. Again direct the spray away from desirable plants.
If the mould is difficult to remove, use a pressure washer instead of a garden hose.