Be careful of how your roof is cleaned and who is cleaning your roof. There are a number of companies cleaning roofs in Snohomish. Roof cleaning CAN easily damage a roof if you do not know how roofs are constructed and what keeps them working. Most roofs are made of asphalt composition and cost in the range of $500 per 100 square feet. Cleaning a roof poorly can significantly reduce the life of the roof and in some cases may create leaks forcing the homeowner to replace the entire roof.
Asphalt composition roofs are made of a fiberglass mesh that is covered on both sides with asphalt tar. Asphalt is a soft pliable material that contains oil based solvents that keep it pliable. Heat, UV rays, and time force the solvents out of the asphalt. When this happens, the asphalt becomes brittle. It cracks and breaks under the stress of the wind and leads to leaks in your roof.
Shingles have a layer of colored mineral crystals that reflect the suns rays and UV light. This layer slows down the emission of the solvents into the air, keeps the asphalt pliable and increases the life of the roof. As the shingle ages, the crystals no longer adhere as well and are easily knocked off the shingles. You might have seen a pile of them in your gutter system. This is an even bigger problem in areas like Marysville where lots of housing tracts are going up on clear cut lots with no trees, making Marysville roof cleaning technique even more important.
It is important for a roof cleaner to protect your crystal layer. That means refusing to clean a roof that is too old and too brittle. It means not using high pressure water that will literally knock the crystals off the shingles. It means not using a scrub brush that will do the same thing.
A quality licensed roof cleaner knows these things. They are also trained roof maintainers that are licensed by the state and pay workers compensation for all workers on your roof. Because of that they make sure their roof workers are well trained and safe. It is expensive to train workers, slows them down on your roof with safety equipment, and requires paying high premiums for workers compensation. You can find independent workers that follow none of these rules and charge less. If they get hurt on your roof you are liable as the general contractor. Not only might someone get hurt but you could get sued.