HOW CAN IT BE CLEANED?
Typical roof cleaning methods involve either pressure cleaning or chemicals solutions containing Chlorine Bleach or Sodium Hydroxide. If used properly, these methods will clean the roof with minimal adverse impact.
WHAT IS THE BEST CLEANING METHOD?
Each method has its advantages and disadvantages.
A chlorine and water solution can be used followed by a thorough rinse. The benefits to using chlorine include a much faster cleaning process and minimal rinsing as compared to the other methods. This translates into much less wear and tear on the roof - particularly asphalt shingle roofs.
Sodium hydroxide based cleaners are generally advertised as safer for the landscaping, but sodium hydroxide is caustic, very toxic, and care should also be used to protect employees and surrounding property. Sodium hydroxide is also a very effective degreaser. So high levels of sodium hydroxide in a cleaning product can cause damage to an asphalt shingle roof that can be irreversible. These products generally require much more rinsing than the chlorine method. The rinsing process is not only time consuming, but it can also be potentially damaging to the roof if not done correctly.
Pressure cleaning has the advantage of not requiring chemicals, which eliminates some of the cost - in addition to landscaping and chemical exposure concerns. The down side to pressure cleaning is that it exerts force that can wear away the surface on some roofs if used repeatedly.
1. How to Pressure Wash your Roof
After following the steps for preparation of the job, proceed in two phases. Water pressure under 2000 psi should be sufficient for a quick and efficient job. Begin from a corner of the roof and work your way down, from top to bottom. Keep the spray at a 45-degree angle with the surface to avoid gouging and move the nozzle in even strokes at a distance of 8 to 10 inches from the roofing material. First power wash the entire surface with an environmentally safe soap to remove mold and fungus. Don?t let the cleaning solution sit for more than 10 to 15 minutes, particularly if the roof is hot when you are power washing it. Next wash everything again with water to remove the grime and residue. Finally rinse with plenty of fresh water. If you encounter stubborn stains, attack them with more soap and more water, and if necessary move the power washer over the stain several times.
2. Recommended Frequency to Power Wash your Roof
Power washing your roof will extend its life, and prevent any health hazards from the accumulation of fungus or mildew. Additionally, a moss and fungus covered roof will absorb more heat and therefore increase your utility bills. The recommended frequency to clean your roof depends on the location of your home. In the northern states roofs can go longer between cleanings but wherever they are exposed to high temperatures and humidity year round, they need to be cleaned at least every three to four years. Whichever the case, avoid using your power washer if temperatures are near freezing as you may risk damage when the drained water freezes.
3. How to Prepare your Roof for Pressure Washing
The first element to consider is the type of power washer that you will use. A regular pressure washer will do a good job, in particular if you add some useful pressure washer attachments such as a 15-degree spray nozzle and a good quality detergent. If you are looking to speed up the job, however, you will need a flat surface cleaner. Although at an angle, a roof is in fact a flat surface for power washing purposes. Start by cutting away any overhanging or protruding tree branches to allow the roof to receive plenty of sun and aeration. Remove debris and any obstructions from the gutters and make sure that the water will drain freely. Test the power washer on a small section of the roof to make sure that the pressure is adjusted correctly and the spray will not cause any damage to the roofing material. Depending on the complexity of the job, hiring a professional pressure washing business may be your best bet.
4. Choosing your Power Washing Chemicals
There are several options of cleaners that professionals use to clean your roof, but many include bleach. The disadvantage is that bleach will discolor your walls and siding wherever it streaks down, and will also kill any plant or animal life along the way. If you are looking to pressure wash the roof yourself, consider using an environmentally safe product such as Biocleanse. This is not only important to protect your house and plants, but also for your personal safety because the inevitable back spray from washing will end up on you as well. A good quality power washing chemical will reduce total cleaning time. Rinse with plenty of fresh water after you are done.
