Please remember to not ever pressure clean your shingle roof. I am sitting in a deposition where State Farm is alleging that damage to the roof was done by pressure washing the roof, not storm damage.
Also pressure cleaning a roof even with low pressure may void the shingle warranty. Here is an article of the issue.
Why You Should Never Pressure Wash Your Roof Shingles
You come home one day and your neighbor’s roof looks spectacular and so clean! It can’t be a new roof because roofers haven’t been there. So what is it? The neighbor had their roof pressure washed. Now you’re thinking of having your roof “cleaned” too. After all, his roof looks brand new, and well…yours doesn’t.
Stop right there. Your neighbor just made a huge mistake. Never, ever under any circumstances pressure wash your roof shingles on your own or pay a company to do so. Sure, it’s tempting to want to get any moss, algae, dirt, etc. off of your roofing shingles. But pressure washing your asphalt roof will do more harm than good. Yes, it will make it look sparkling clean, but also you’ll end up replacing the roof system sooner rather than later.
The damage caused by pressure washing is not immediately noticeable. Pressure washing strips the granules from asphalt shingles. Therefore it strips away years of your roof’s lifespan. These granules are what enable your roof to protect your home from the elements, like rain, wind and sun.
A 15-year-old roof has fewer granules to spare than a newer roof does. Older roofs are usually the ones that look like they could benefit most from a “good cleaning.” But keep in mind pressure washing an older roof is sending it to its grave all that much sooner.
Some roofing companies claim to use a low-pressure wash with a special tip to clean roofing shingles. But even low pressure can damage shingles.
David R. Heil, P.A.