The problem and solution is not too difficult provided one understands from the start the dynamics of shingle roofs – how they are set up, what the problems are relating to the types of stains that need attention. It is not any and everybody who can operate a pressure washing company because although the matter is simple nevertheless the fundamentals have to be grasped. The next step is experience leading to technical expertise.
If the contractor does not understand the basics of roof installation then thousands of dollars may go down the drain. The pressure applied must be minimal and low so that the shingles are not affected. Before starting the job the roof must be thoroughly inspected and checked. Most of the pressure wash machines used for cleaning the roof use 4 GPM and even go up to 10 GPM. One must know when to use what. It depends on specific conditions and the discretionary powers of the contractor.
In most cases of roof construction, a layer of felt is first laid out and on top of this other roofing materials are applied. The first shingle layer is known as the starter-course and is installed at the lowest tip of the roof in reverse position. This forms a solid base over which water can run out without sneaking and leaking into the rafters. These are laid between the shingles key ways. A second layer of shingle is installed directly on top of it and the rest of the roofing is laid in the same way going up the line of the roof. This allows the water to run from one level of shingle to another before draining into the gutter. This is the first basic step about roof installation.
Having studied the anatomy of the roof now is the time to think about the remedy – that is cleaning of the roof. The most common roof ailment of the roof is the formation of a fungus growth called Gloeocapsa Magma. It is carried by wind and air and will anchor on any type of roof. It is a silent killer and escapes the casual notice of the owner of the house until already considerable damage has been done and large chunks of the roof space have been taken over. This algae initially looks like dark brown or black marks. It multiplies in humid climate.
The method of roof cleaning is very effective in cleaning this dangerous ugly blemish. Some contractors use a mixture of TSP and bleach that instantly destroys fungus. Others recommend the use of a cleaner that has sodium hydroxide as its base. No matter what solution is used the guidelines of the manufacturer of that specific solution must be followed. Companies will guarantee their own products but not that of others. All however are in one voice and warn that high pressure should under no circumstances be used while roofs are being cleaned. Some contractors use pressure ranging up to 600 PSI. The general rule is using the least amount of pressure and the softest chemical to get the desired result.
There is a great demand for roof cleaning contractors but if anyone wants to seriously opt for this as a livelihood the best is to take a course on the subject conducted by The Power Washers of North America (PWNA). Its itinerary is extremely informative and of practical use. Knowledge will be gained about the different chemicals being used as well as the techniques of application.