Can You Power Wash A Roof

The simple and direct answer: absolutely not. Never use a high-pressure water gun on an asphalt shingle roof. Many people think this is a “shortcut” to clean up black spots or moss, but this high-pressure scour will directly strip the protective layer of mineral particles on the surface of the tiles. Once these particles fall off, not only the manufacturer’s warranty will be directly invalidated, but the aging rate of the roof will also increase geometrically, with water leakage and structural damage. Finally, the maintenance cost you take out can be much more expensive than the cleaning cost.

Why Is High Pressure Cleaning The “Killer” Of The Roof?

The high-pressure cleaning does have three fatal injuries:

Physical Wear And Particle Loss

The layer of mineral particles on the surface of the asphalt shingle is its “sunscreen” and is specifically designed to protect against ultraviolet rays. The high-pressure water flow acts like sandpaper and will forcibly wash these particles away. Without the protective layer, the tiles become brittle and hard, and the life of the entire roof is counted down in advance.

Structural Damage And Water Infiltration

The high-pressure water column not only hurts the surface, but also drills holes. It can easily open the gap between the tiles, and even the water pressure into the waterproof layer, resulting in hidden leakage. In the case of a tile roof, the high-pressure water flow will also wash out the sealant strip. When many non-professionals climb up to clean themselves, the cracks in the tiles caused by improper trampling are impossible to prevent. They cannot be seen from the ground at all, and they have already suffered heavy losses when the water leak is found.

Factory Warranty Direct Scrap

If you go through the warranty manual on the roof, you will find that almost all manufacturers are explicitly prohibiting high-pressure cleaning. Once you move your hand, the warranty terms are voided. After the roof is really out of the question, as long as you see the traces of washing, manufacturers will definitely be “improper maintenance” on the grounds of refusing to claim.

Author: Alex Miller

I have spent over 12 years in the roofing and exterior maintenance industry. Having witnessed countless roofs suffer permanent, costly damage from improper high-pressure cleaning, I have made it my mission to educate homeowners on the science of ‘soft washing.’