How to clean moss off a stone wall
Moss -- a small, nonflowering plant -- thrives in moist areas that have low light. Moss can be found growing on a variety of surfaces, including trees, houses and stone walls. Moss growing on stone walls can add a natural, fairy tale look to your surroundings.
Unfortunately, the moss can damage the stone wall and cause discolouration. Stains caused by moss can be difficult to remove. It is important to remove the moss as soon as possible to prevent damage to the stone.
Rinse the stone wall with a water hose. Use the pressure from the water hose to remove the moss. Use a stiff-bristled brush broom to remove stuck-on moss.
Put on a pair of rubber gloves to prevent skin irritation. Mix 1 gallon of water with 1/2 cup of bleach in a plastic bucket. Alternatively, use a stone cleaner that contains phosphoric acid.
Dip the stiff-bristled brush broom into the water-bleach mixture. Start scrubbing the bottom of the stone wall, and work your way up.
Continue scrubbing the wall and saturating the broom in the mixture until the stone wall is clean and free of moss.
Rinse the mixture off the stone with a water hose. Begin at the bottom of the stone wall and move the water hose upward in a back-and-forth motion.
Allow the stone wall to air-dry.