Roof Washing - Asphalt
“Zero Pressure roof washing” is a new concept that has been perfected by our company through years of research and development. In the past it was almost always necessary to use at least 600-1000 PSI to achieve desired results but we have developed a solution that eliminates the use of pressure most of the time on asphalt roofs and 100% of the time on cedar shake roofs.
What sets us apart from the rest? We use a special proprietary blend of cleaning agents that will not only kill all of the growth, it will greatly lengthen the time required between cleanings. This solution will not harm people, plants, or animals and is not harmful to the roof itself. Many companies will use strong sodium hydroxide cleaners at concentrations of up to 20%. This will quickly kill all growth but is also extremely dangerous for the applicator as well as the customer and the surroundings. In addition, these strong emulsifiers will quickly break down the backing that holds the shingle together greatly shortening the life of the shingle. Our solution is much safer and less toxic and is safe for you roof.
You might ask yourself “why should I clean my roof? I don’t see it anyway, and it not hurting anything... right” Wrong! Roof washing is not only important to the appearance of your property but it is also necessary. The growth on your roof is contagious to the whole neighborhood as it is airborne. In addition, if not properly cleaned your roof can eventually grow moss which will cause irreparable damage to the structure of the shingle.
To find out more about the fungus Click Here.
The prehistoric organism that streaks your shingles
Black streaks running down your roof aren't a sign that the asphalt shingles are dissolving or that you need a new roof. Rather, you have roof algae.
The organisms arrive on the rooftop as either spores or clumps of cells. If they land on the north side of the roof, where the sun is less harsh and moisture more plentiful, the algae will have a good environment to multiply, spreading in a delta down the slope of the roof.
Asphalt shingles contain limestone, which makes them heavy, durable and reflective. Roof algae over time will slowly consume the limestone, ultimately weakening the shingles.
Algae cells produce a dark pigment that acts as a sunscreen, protecting the cells from the sun. As this pigment accumulates on shingles, the roof becomes less reflective and absorbs more sunlight, which is transferred into the house as heat, raising cooling costs.
Roof algae are the first wave in a succession of organisms that can colonize and ultimately undermine a roof. The algae can eventually team up with a fungus to form lichen. Moss follows, building a small layer of soil that might catch seeds from bird droppings. By the time grass sprouts between the shingles, it's past time for a new roof. The process can take years.
An ancient organism
The growths on the roof are cyanobacteria, or blue-green algae, a phylum of organisms that has dwelt on Earth for about 3 billion years. As primordial photosynthesizers, they were the originators of oxygen in the atmosphere. Gloeocapsa magma is the species that blackens roofs.
Cleaning an affected roof
Roofing experts warn against using pressure washers on asphalt shingles because that can damage the shingles and do a poor job of removing algae.
Roof algae, Gloeocapsa magma, illustration by Patterson Clark Roof algae most often grows beneath trees and on a roof's north side.
Instead, professionals use a low-pressure application of bleach and water, which kills the algae and restores the shingles.
However, bleach runoff can be a potent pollutant, so care must be taken to protect plants, soils and aquatic ecosystems.