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The Harmful Effects of Using White Zinc Powder on Roofs

Posted August 10, 2022 by Tim Mueller
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Have you ever wondered why a neighbor has white powder on their roof? It is no great mystery. They applied it to control moss growth on their home’s roof.

The substance is zinc sulfate powder. Homeowners use it as a moss control powder to rid their roofs of the slimy green stuff. This type of moss deterrent comes in two forms, a zinc sulfate powder or a zinc strip.

Moss is a stubborn little beast that can grow almost anywhere. It thrives in humid and shady conditions, especially on rooftops. Moss can also be quite an eye-sore, especially in a well-maintained home.

Many homeowners use white zinc powder for moss removal to make the rooftop look new. However, you should know that this practice of moss control has proven to cause more harm than good to roofs in the long run. Read on to learn why you should never use white zinc powder for moss removal if you want your roof to last longer than it already will.

What Is Zinc Powder?

White zinc powder is a toxic substance used as an effective chemical-based method for removing moss from roofs. It is a powdery substance made from zinc sulfate and is very corrosive. The toxic, corrosive nature of zinc sulfate is why it is not recommended for use on the exterior of your roof.

Sulfur and zinc combine to form zinc sulfate. It is a herbicide generally employed to eradicate moss. The amount of zinc in the product determines how hazardous zinc sulfate is.

For the nourishment of people, animals, and plants, zinc is a crucial mineral. Natural sources of zinc include the environment, food, and water.

However, zinc sulfate in excess causes serious issues. Since 1973, compounds containing zinc received authorization for use in pesticides in the US. Do you want to use pesticides in the form of zinc powder on your roof? 

3 Reasons Why White Zinc Is Bad for Your Roof

White zinc powder harms the growth of moss, and many homeowners use it for roof moss control. However, it is crucial to understand that it can also cause damage to the very roof that it is supposed to protect.

When you apply white zinc powder to the surface of roof shingles, it starts to break down the shingle material. Over time, the zinc will become corrosive, degrading the shingles, which can cause them to fall off or become brittle.

When applied, zinc powder also has the potential to harm your roof’s underlying surface. This is especially true if the roofing has a zinc coating or surface membrane that is not resistant to alkaline solutions. 

Zinc Powder Causes Discoloration

The white zinc powder will turn the roof of your house green. This is because the moss will absorb the zinc, and the roofing will become discolored due to the excess zinc left behind on the roof.

While discoloration of the roof is a natural phenomenon that happens over time, zinc is an aggressive substance that causes visible and immediate discoloration. It is best to stop the damage before it happens rather than trying to reverse it once it is already there. 

Causes Deterioration of the Materials Used on Your Roof

The shingles, which happen to be the most common material used in roofs, have asphalt in their construction. This makes them very susceptible to alkaline solutions. As such, when the shingles have exposure to the white zinc, they will most likely deteriorate.

This deterioration can manifest in the form of discoloration and crumbling of the shingles. The shingles will start to fall off the roof, making it easier for debris to enter the house.

It depends on the brand of shingles and the type of zinc used. But, the deterioration may even happen within a few weeks. 

Zinc Powder Will Corrode Metal Fasteners and Gutters

Due to the corrosive nature of white zinc powder, it also has the potential to harm the other components of the roof. This is especially true for metal components.

Since zinc is a corrosive substance, it can corrode metal fasteners—like nails and screws—and cause them to rust. When the metal fasteners rust, they can weaken the structural integrity of the roof and may cause leaks.

It can also make it more difficult to repair the roof when needed. When using zinc on the surface of the roof, it also has the potential to corrode down the gutters, which can then cause water damage to the home. 

Effects of Zinc Sulfate on the Environment

When using white zinc on your home’s roofing, it will likely enter the environment in one way or another. It will either run off the roof and enter nearby water bodies when it rains or seep into the ground and reach the groundwater.

When zinc enters the water, it is harmful to aquatic life, including both freshwater fish and saltwater organisms. It can also cause damage to the plants and trees that are around the water bodies.

As was already noted, the sulfates in zinc powder on a roof can leave a negative impact on the environment. Zinc sulfate and titanium disulfide, which are tiny and nanoscale in size, offer effective defense against UV radiation. The rest of the powder can impede plants’ normal growth cycles when it comes into contact with them.

Since the sulfate is not soluble in water, it remains floating above the water’s surface and moves from one surface to another. Microscopic zinc powder particles can enter lakes, streams, oceans, and rivers in areas where it rains often. The basic species that gauge the quality of their surroundings are “indicator species,” and using zinc sulfate may injure them

Breathing Problems Caused by White Zinc Powder

One of the most serious harmful effects of white zinc is that it can cause breathing problems. When you choose to use white zinc powder on your roof, it can come in direct contact with the skin. If the dust from the powder gets inhaled, it can cause breathing issues and irritation in the lungs. 

Zinc sulfate inhalation can harm the respiratory system, bring on nausea, vomiting, stomach pain, disorientation, depression, and even death. Skin injury from exposure through skin contact can result in blisters, ulcers, and scars. 

Other Harmful Effects of Using Zinc Powder on Your Roof

Apart from the issues mentioned, there are other harmful effects of using white zinc powder for moss removal. White zinc can also cause damage to the surface of the roof and shorten its lifespan.

You should avoid using white zinc powder for moss removal if you want your roof to last longer. Treating your home’s roof with a toxic substance can cause more damage than good.

It could even make it difficult to repair. Instead, think about using non-toxic methods for moss removal.

Alternatives to Your Roof Moss Problem

Why should you pay a roofing contractor to use zinc powder to remove roof moss when it will end up looking like someone threw up on it? Your roof’s appearance will look worse than it did before! Using zinc powder leaves ugly traces of white and green streaking that will make your roof appear dirty and unkempt.

You should find out what your roofing contractor uses to prevent and eradicate roof moss. A pH changer made of sodium silicate that is entirely eco-friendly and non-corrosive is used by Roof Life of Oregon.

Always hire a professional when looking to remove moss growth on your roof. They have the tools and know-how to keep the moss growth at bay. There are non-toxic methods for removing moss in the Portland area without causing any harmful side effects to you or the environment. These methods do not include white moss control powder. Contact us or check out our Blog section for helpful information.

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