Should You Pressure Wash Your Roof Shingles?
The answer is unequivocally no! Proper roof maintenance is important but it should be done by someone with the correct knowledge and skills. You or a licensed roofing contractor should inspect your roof for overall shingle integrity, cracked or curling caulk, worn or cracked boots, and cracked or rusted flashing. If you have a chimney it should be inspected as well. Then, hire an experienced Soft Wash company to treat your roof for algae, moss, and lichen. Having your roof treated will greatly improve its appearance, and prevent damage caused by unwanted plant life. Whether your goal is to prevent damage or to improve curb appeal, having your roof treated is an important part of its maintenance.
So why not just get out your trusty power washer and blast away the moss and algae on your roof? There are four very good reasons not to:
1) Using pressure on your shingles can cause leaks. Your roof is meant to protect your home from the elements, but if a strong storm comes through it’s a good idea to have your asphalt roof inspected for damage. Your shingles are not meant to stand up against tornadoes, severe straight line winds, or hail. A standard pressure wash is closer to the severe storm category than your typical downpour. Your roof just isn’t meant to have thousands of pounds of pressure blasting water at it.
2) Using pressure can rip shingles right off of your roof. Just like with a severe storm, sometimes roof damage doesn’t mean replacing the whole roof. You can replace just the missing or damaged shingles if the damage isn’t too wide spread, but do you really want to? One of the temptations of having your roof power washed is to get the dark algae covered sections to match the cleaner areas of your roof. If shingles are blasted off in the process it will be nearly impossible to get a perfect color match with new shingles. A skilled roofer will blend the sections as much as possible but it won’t be perfect; and it is a completely avoidable expense.
3) Pressure washing will remove the shingles’ protective granules. Asphalt shingles are covered in protective granules. These granules have three important functions. First, and most importantly, they help your roof shed water. Second, they help protect the asphalt layer from damaging UV rays. This prevents premature aging of your shingles just like sunblock for your skin. Last, but certainly not least, they also increase your roof’s fire resistance. Shingle granules will inevitably and gradually come off with normal use and proper maintenance, but having your roof pressure washed will mean replacing your roof much sooner than you expected.
4) Pressure washing voids the manufacturer’s warranty on your shingles and your homeowners insurance policy. So far I’ve only wrote about the damage a pressure washer will cause, but number four is the most important reason not to have your roof pressure washed. If your shingles are defective the manufacturer will normally replace them. If your roof is damaged in a storm your homeowners insurance will pay to have it fixed. However, in both instances a trained inspector will come out and take a very close look at your roof. If your roof shows the tell tale signs of being pressure washed, you are completely out of luck. Replacing your roof is no small expense, and having your roof pressure washed means paying for any damages yourself.
The answer is to have your roof treated by a company that specializes in soft washing. These companies will spray your roof with a fine mist to treat the algae, moss, and lichen growing on your roof. The treatment will immediately kill your unwanted house plants and return your roof to its original color. While the dark areas caused by algae are removed right away, the moss and lichen are a little more stubborn. While the treatment will kill them, they need time to dry up in order to detach their roots from your shingles without causing damage. Once these stubborn plants have safely detached they will roll off during the next rain.
A true soft wash company will use professional products that have been approved by shingle manufacturers as well as insurance companies. They will also use specialized equipment. If a company tells you they can soft wash your roof with their pressure washer, find a different company!