What are those black stains? They are a form of algae that grows in the shady areas on your roof. The good news is they can be cleaned using the proper mixture as well as technique, restoring the look of your home’s shingles and giving you that extra WOW factor. We here at Innovative Glass have reached out to just about all shingle manufactures that cover our area as well as local roofing companies and have discussed how to remove them and maintain your roof.
First off, and I have seen this many times, do not use a normal pressure washer on your roof, recently many pressure washing services have begun to offer roof cleaning, but using a high pressure on your roof will damage the granules on the shingle and your 25yr warranty just went to zero as this voids it. Using very low pressure (or soft wash) which operates at around 40 psi, using a mixture of high concentrate bleach and surfactant, gently spray on the effected areas and let sit for 20 minutes, then begin rinsing again using no pressure, although this will clean the roofing surface, over time they will come back.
For the home owner, if the roof is walkable a pump sprayer will suffice and rinse with a water hose. It is very important to spray with clean water all plants around your home, as well as use proper PPE, i.e. Safety glasses, mask, and clothes you don’t mind getting ruined.
For us, learning the proper processes to clean your home was very vital. We teach our employees to inspect a roof for damage, and this is also a great time for the home owner to brush up on roof damage and inspect your own roof.
The recommended Roof Cleaning mixture should be close to a 50/50 ratio of bleach to water, with a surfactant to help it ‘stick’ to the roof while it does its job. For tougher areas where lichen and full on algae growth has formed, you may have to come back and gently remove that dead algae being careful not to damage the granules.
After speaking with roofing manufactures and roofing companies, they do offer a algae resistant shingle, but this only covers certain types of algae and mold, not all. But it is recommended to get your roof cleaned occasionally to maintain the roof as well as appearance.
If you live in Knoxville or the surrounding areas, give Innovative Glass a call 865-455-9871 for a FREE estimate on all your roof cleaning or Pressure Washing needs. We are happy to assist you, even if it is to just answer questions.