Metal Roof Stains

There are a lot of different substances that can build up on your roof.

Metal roof stains.

Most of these substances can be removed by a mixture of cup tri sodium phosphate and 1 gallon of water. These substances can infiltrate the limestone mixture that attaches the shingle to the roof and end up harming its ability to repel water. While doing little harm to your shingles the black streaks caused by the algae are unsightly. These red brown or even black roof stains are often caused by corrosion of on rooof or above roof metal components but may also be the result of improper combustion of wood coal or oil fired possibly also gas fired heating appliances vented above the roof.

Algae can be killed and the stains removed using chemical cleaners though they usually return over time. But here s the kicker. And the runoff harms plants. Bleach may kill the top layer of algae and lighten the stains but it doesn t kill the underlying algae.

Your stains are probably caused by the airborne spores of a blue green algae known as gloeocapsa magma which is often mistaken for mold or mildew. A clean roof looks wonderful on a house but if you have metal roofs rust stains can become a problem. Algae tree sap and leaves moss and many other materials get dropped or blown onto your roof. Roof stains are not only unappealing to look at they also compromise the waterproofing ability of your shingles.

These days they re often very elaborate and available in different colors to match the rest of your house. It can lighten the color of your roof and bleach anything the overspray contacts. Pine sap decaying leaves and even road dirt that s drifted into the air can settle on your metal roof and stain it. Plus chlorine bleach is a corrosive agent that can damage metal roof flashings gutters and downspouts.