How to Remove Mold or Algae from a Metal Roof

Due to the inevitable accumulation of dust and dirt, metal roofs may attract algae, lichen, and mold over time. Other factors, such as your home’s proximity to overhead trees, as well as the presence or absence of sunlight, may also bring other pollutants to metal surfaces that could affect the cleanliness of your roof. This may surface common questions like “How do I clean a stone-coated metal roof?” 

To clean your roof, carefully consider the following practices:

• DO take all safety precautions, including fall safety measures, while cleaning your roof.

           Your safety should always be your top priority during any home improvement project, so we encourage everyone to take the proper precautions before cleaning a stone-coated metal roof. Safety tips include:

            ①Implementing fall safety measures, such as installing proper ladders or scaffolds for entering or exiting safely.

            ②Avoid no stepping zones.

            ③Use protective gear.

           You’ll also want to make sure you disconnect your roof cistern collection systems to avoid contamination when cleaning your roof. Allow the roof to flush at least three rainfall occurrences before reconnecting roof water run-off back into the cistern collection system.

• DO use cleaning and post-wash algae, mildew, lichen, moss preventative products that are not corrosive and will not harm your lawn and garden.

• DO disconnect roof cistern collection systems to avoid contamination when cleaning your roof. Allow the roof to further flush via at least three rainfall occurrences before re-connecting roof water run-off back into the cistern collection system.

• DO NOT use copper- or iron-based products or solutions to clean or treat a roof for algae, mildew, lichen, or moss growth. Copper-based products or solutions accelerate corrosion to roof panels, due to dissimilar metals galvanic reaction. Iron-based products will rust stain your roof.

• DO NOT use water pressure above 500 psi. Carefully use water spray more for a rinse procedure rather than a primary dirt and algae, mildew, lichen, moss removal method. AVOID forceful removal of roof panel stone coat granules in all instances.

• DO NOT exceed 160 degrees (F) water/solution temperature if using a heated water/steam type cleaning apparatus. Instead, carefully spray water from a hose as a soft rinse procedure and wipe away any algae, lichen, mildew, moss, or other visible pollutants that have accumulated to better maintain your roof.

More metal roof cleaning tips:

①Trim any tree branches that impede the roof or block sunlight.

②Clear debris on top of the roof.

③Clean your gutters to prevent build-up of leaves and/or branches.