Some companies charge based on square footage and others charge based on the difficuly in accessing and cleaning the room as well as potential liability. Washing a roof is a bit more involved than cleaning the exterior walls of a home in terms of chemicals, difficult, liability, and safey and so these costs are considered when quoting roof cleaning jobs but depending on the height, size, and material of the roof itself a roof wash can range from a few hundreds dollars for an average sized home to above a thousand dollars on much larger homes.

A driveway should be cleaning at least once a year to maintain it looking great and prevent the dirt and mold from staining the concrete. If you have oil stains, they should be cleaned as best as possible immediately after the spill. Oil spills that sit in the porous concrete long are likely not to come up completely even with professional chemicals.

Roofs can be made of different material and materials are considered when cleaning but professionally, roofs are cleaned by a method called softwashing which is essentially low pressure and applying specific chemicals in appropriate concentrations to remove mold and mildew.

You don’t necessarily need a pressure washer to clean a roof and you definitely should not apply pressure to shingles and you can remove the granules and reduce the lifespan of the roof. Adequate mold-killing chemicals need to be applied evenly and in proper concentrations to clean a roof. Without the proper equipment it could be less safe and efficient, however.

Lichen can begin growing on the roof and mold that has been left to grow that long can discolor the shingles and reduce the lifespan of a roof, more specifically shingle roofs.

Apply the proper chemicals and low pressure when cleaning shingles. High pressure should never be used on shingles as they will certainly be permanently damaged. After allowing to dwell, an adequate rinse will do the job but be sure to pay attention to plants and property that may be oversprayed by chemicals.