Maintenance
August 29, 2024

Roof Washing FAQ

Roof Washing FAQ

I’ve never heard of Roof Shampoo or roof cleaning. Why should I clean it versus replacing it?

The algae, Gloeocapsa Magma, is an airborne spore that has been prevalent in the southern states for decades, and had been working it’s way north. Cleaning the algae from your roof may extend it’s life, saving you money. The cost of a Roof Shampoo is a fraction of the cost of a new roof. If your shingles just have algae, but are otherwise in good condition, cleaning and regular maintenance may add several more years to your roof’s life.

Are all roof cleaning companies the same?

No. Each company uses different solutions, and techniques. We believe our process is the safest for both your roof and the rest of your property. Zablocki Roofing has been doing business in the St. Cloud area for over 15 years. We are licensed, bonded and fully insured. We know how to be on your roof with both our safety and protecting your roof in mind. (Please NOTE: Currently there are no licensing guidelines for roof cleaning. Use caution when hiring ANYONE to do work on your property!)

Can I clean my roof myself?

We do not recommend homeowners attempting this home improvement project. The products that you can buy at home improvement stores do not have the same coverage as our product, and may end up costing you more than our service.
Some products recommend that you apply their product, wait a few hours then rinse the product off (meaning you have to access your roof several times). Other products do not kill the algae, our product kills the root of the algae where it started growing.
Some products actually recommend using a brush to “scrub” the algae off. When you have to “scrub” you are working granules off your shingles, shortening their lifespan.


Most of the over the counter products warn you to use caution around plants and animals as it can be harmful to them. The product we use is safe for the environment, any type of vegetation and your pets.

Can I just use my pressure washer to clean my roof?

No, never use a pressure washer on your shingles. The algae is embedded in the granules of your shingles and you would need to use too much pressure to wash the algae away, taking excess granules with the algae. This method will shorten the life of your roof, causing you to replace it much sooner than necessary.

It looks like you are using a pressure washer – how is that different?

We use a pressure washer to mix the correct amount of solution to water. The wand and washing disc that we have attached disperses the diluted solution at the same strength as a gentle summer rain. The solution kills the algae, and the water washes it away. The key is not to use high pressure but use about enough water to rinse of the roof.

Can I call in to get an estimate over the phone?

No. Every house is different. Are your shingles in good condition, so that our service would be a benefit to you? Is your entire roof affected by algae, or only part of the roof? How steep is your roof? How many stories? What type of landscaping do you have? Do you have pets or wildlife in your yard?
We want to be able to provide you with an honest price, and to do that we need to see your property and take in all of the considerations to be of service to you.

My shingles are really dirty, can you clean them?

This is why we need to come to your property, so we can see first hand what is happening with your roof. If your shingles just have algae, but are otherwise in good condition, yes, we can clean your roof. If your shingles have other issues, however, cleaning may not be recommended. We take “before” photos and if there are any issues will show you.

My shingles are “Lifetime”, why do I need to replace them so soon?

Do you take your car in for maintenance? Do you repaint or reseal your windows periodically? You perform regular maintenance on several items every day. Your roof is no different. Regular maintenance is the key to ensure you get as many years as possible from it.

I was told my roof is just “dirty”.
Pollution does not stick to your roof. It would be washed away in the next rain. The black streaking is an algae called Gloeocapsa Magma, an airborne spore that feeds on limestone. Shingle manufacturers have been increasing the amount of limestone filler in their shingles as oil prices have increased.

Is Gloeocapsa Magma really going to damage my shingles?

This algae creates a “dirty” appearance to your home, lowering the curb appeal. Currently the science is split on whether this algae actually damages your roof. Shingle manufacturers will tell you that while this may be aesthetically unpleasant it does not shorten the life of your roof. Please note, however, that if you need to replace your roof more often the shingle manufacturers do benefit.
Roofers and roof cleaning companies have seen how the algae attaches to your roof. The algae can cause the shingles to curl, which then allows rain and moisture to seep into your home. We see the damage this invasive species can cause and are trying to minimize its spread. There has been some information that as the algae spreads, it will work it’s way past the shingle granules to reach the limestone in the shingle. This, than can cause granule loss since the granules are attached to the limestone and asphalt of the shingle.

What would happen if I decide not to have my roof cleaned?

What would happen if you choose not to change the oil in your car? You would need to replace it sooner than if you did the regular maintenance. The same process applies to your roof. Regular maintenance and upkeep will extend the life of your roof, allowing it to keep moisture away from your home’s interior.

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