Mosses are small, soft plants that are typically 1–10 cm (0.4–4 in) tall, though some species are much larger. They commonly grow close together in clumps or mats in damp or shady locations. They do not have flowers or seeds, and their simple leaves cover the thin wiry stems. At certain times mosses produce spore capsules which may appear as beak-like capsules borne aloft on thin stalks.
If moss is growing on your rooftop or over your concrete driveway, you have reason to be concerned. Moss can cause damage, and it is best to get rid of it as soon as possible. Moss can damage your masonry surfaces. It damages a masonry surface by dissolving the calcium and/or lime in the concrete surface. Leaving moss to grow for an extended period of time can lead to costly repairs.
Moss can also cause a slip and fall hazard in the areas outside your home. Slippery paths and steps covered in moss can be, well, slippery! Winter is traditionally the time when algal, moss and liverwort growth is most significant, but build-up can occur during any wet period or in shady, humid areas.
Power washing is the most effective way of dealing with this problem. A professional power washing service is recommended to minimize the amount of damage to your mossy areas. (IE: surrounding plants, exposed aggregate, wood fencing, decks, etc.)
The end result will be far superior to most small do-it-yourself retail electric or low HP gas units. At Greenway we use commercial equipment and skilled operators.