A common misunderstanding is that all roofs are created equal. There are too many factors for this to be true. You have to consider that not all roofs are made of the same material. You have metal, shingle, wood shingle, tile, and metal tile roofs. Many roofs are very hard to traverse due to varying pitches and materials. This makes for a very dangerous business to have a one-solution method.

Some companies believe there is a single solution for cleaning a roof and have adopted this method. This is the use of extremely potent chemicals sprayed on in massive quantities. This makes the algae stains on the surface magically disappear. In the 1980’s when many roofs were shingle the chemical solution was the widely accepted solution. This was due to damage to the shingles from pressure cleaning causing granular loss. That fact is still true, shingle roofs cannot handle pressure cleaning. Shingle roof owners do not have a choice. If the process is done correctly by chemical cleaning the contractor is able to prevent extreme granular loss.

Any chemical process or softwash roof cleaning should always be rinsed from the roof. The longer you leave any chemical on a roof the more damage it is doing. Never have a company mislead you to believe that the longer a chemical stays on your roof the more it is helping or that it will extend the cleaning. These are called spray-on-leave-on methods. Many roofing materials are prone to rust and other cellular damage from excessive exposure to chemicals. This can include nails, flashing, tar paper, shingles, and other building materials.

As for tile roofs chemical cleaning is not the best solution. It is the opposite, although this practice has been adopted across the board. The strength of these chemicals has to be so high with no dilution available for these processes to work. These chemicals can get caught in cracks and crevices for long periods under the tiles. This is especially true when you have tiles butting together in valleys.

Many of the new building codes in the state of Florida require you to foam-fill air space under the tiles for hurricane protection. This allows more areas where chemicals can get caught and also allows more roofing products to be exposed to chemical damage. The use of chemicals is necessary for cleaning all forms of roofs including tiles. The right type of contractor will use less than 5% of the chemicals that (chemical only) type companies may use. This is accomplished by having an appropriate mix of chemicals and agitation from pressure washing.

 It is a commonly known fact in any form of cleaning that chemicals are more effective with agitation. For this reason companies that pressure clean tiles do not have to service their contracts as often as (chemical-only) spray companies.