Several years ago this client had this boat barn built in Seadrift about 1 block from the water. As you can see on the north side of the building, moss and algae has thrived out of view of the sunlight and in the presence of high moisture. This is common along the coastal areas. To complicate things, the painting job by the contractor was substandard and was completed with only a single coat of low quality paint.
About 1 year ago the homeowner hired a contractor to cleanup the algae growing on the HardiePlank siding. As you can see in the picture and reported by the owner, the contractor used high pressure to blast the algae off the siding and the "cleaner"
lower half is all he could reach using his extension ladder. The streaks were not noticeable after he blasted the siding but the algae and mildew remained and grew back quicker where it had not been blasted away. Note the buildup of algae, spider webs and debris under the soffit. Now lets fast forward to today.
When we clean a home, we used a method called Soft Washing that utilizes low pressure and specialized chemicals and detergents to kill algae, mold, mildew, lichens and other vegetation that grow on the home. These specialized chemicals safely cause the vegitation to loosen the grip from the siding and allow it to freely rinse off; meanwhile, using pressure that is safe enough to pass over bare skin without harm. Note: Once the algae and mildew is removed, the evidence of a single coat of paint is clearly evident on the white trim and the use of 2 different tones of yellow paint for the HardiePlank siding.
Our equipment allows us to Soft Wash 2.5 stories without getting on a ladder! Never use high pressure on siding or any other destructible surface. There is high risk of damage to property and water traveling at high velocities can force its way into the seems between planks or vinyl siding causing hidden water damage and mold growth behind the siding that might not be discovered for years and be very costly to repair. Protect yourself and use a professional service that has the knowledge, experience and equipment to properly clean your property and investment.