Why do some roofs have algae on them?

a shingle roof covered in algae and moss

Why do some roofs have algae on them?

The humidity in Cincinnati, Ohio, averaging between 60% and 70%, can damage rooftops. The moisture sits there, the air pollution adds more layers, and it all waits for the sun to bake and create an algae coating. The damage this causes costs homeowners and insurance companies thousands of dollars, and investing in algae-free roofing is a value-add.  

What is algae, and why don’t we want it on our roofs?

Like plants, algae is a group of primarily aquatic, nucleus-bearing, photosynthetic organisms. However, unlike plants, algae lacks leaves, stems, and roots, the multicellular reproductive structures that other plants have. Therefore, you cannot purchase a flat of algae to plant like Begonias and Coleus. 

Aglae are carried in the air, landing on rooftops, latching onto asphalt shingles, and feeding off the limestone granule top layer. When left to feed, they spread, and over time, as they eat away at the limestone, they slowly weaken the shingles. When combined with fungus, another growth you can’t purchase by the flat produces another growth: lichen. This more advanced life form is more destructive, hardier, and sturdier.  

With this in mind, it is clear why algae-free roofing has become a highly demanded roofing material. So, what makes a roof algae-free? The industry manufactures algae-free roofing with substances like copper and zinc granules that stop algae from growing, providing you with significant savings in the long run.

What is the best algae-free roofing?

One key component of algae-free roofing is the use of copper granules. Copper is a valuable barrier against algae growth because it is inedible. You may notice the common usage of copper in plumbing because of its resistance to issues such as algae and corrosion. Every asphalt shingle manufacturer will have its own version of algae-free roofing, but there are some common factors between them, including: 

  • Products that prevent the growth of algae, mildew, and moss. 
  • Products that prevent roofs from stains.
  • Products manufactured with antimicrobial properties.
  • Prevents streaks on the roof.
  • Products that increase the curb appeal to houses.  

Is algae-free roofing ugly? 

No, algae-free roofing shingles are available in different styles, allowing homeowners to coordinate or match their home’s architectural style. By choosing an algae-free roofing material, you’ll be giving your home a level of protection with energy efficiency that is still visually pleasing.

What kills algae on shingle roofs?

A build-up of moss on a shingle roof can cause water movement laterally. This results in the roof deck being damaged by moisture, leading to leaks. If you’ve noticed algae building up on your asphalt shingle roof, you can remove it using a mixture of one-half household bleach and one-half water. 

Can you keep algae from growing on a roof?

If you don’t have algae-free roofing now, you can minimize the substance from building up by keeping it clean and clear of debris and dirt. Keeping the gutters clean is also essential for minimizing algae growth. If your roof gets algae, once you have removed it, inserting six-inch-wide strips of copper or zinc under the shingles along the peak of the roof is recommended. 

What is the best color of roofing to hide algae?

Of course, the best thing to do is to have algae-free roofing installed. The next best thing is to remove the algae and then take the steps we recommended above to prevent algae. 

If you’re getting a new roof and the algae-free roofing material is out of budget range, choose dark-colored shingles. These won’t show algae or stains, making your roof unsightly. 

Are algae-free roofing shingles worthwhile?

Algae-free roofing shingles will cost a little more than standard asphalt shingles. Depending on brand and quality level, the approximate cost of algae-free roofing shingles can start around $2.00 per square foot. Some may be under that, and others may be double or more. 

What is the cheapest type of algae-free roofing shingles?

Asphalt shingles will always be the best bet if you’re looking for the cheapest roofing material, even if you’re looking for an algae-free roofing material. There are three types. Basic three-tab shingles are the most affordable and standard, ideal for tight budgets on houses flipped for profit. 

The other two types of asphalt shingles are architectural shingles and luxury shingles. Dimensional shingles are manufactured with a minimum of two fused, resulting in a multi-dimensional appearance. They are made to look like natural slate or wood shake roofing. Luxury asphalt shingles are considered heavy-weight shingles, giving a differentiated appearance that outclasses dimensional shingles. 

Topping It Off

Is the higher cost of algae-free roofing shingles worthwhile? Absolutely. Here in the Cincinnati, Ohio area, where the humidity can attract algae, go with algae-free roofing if possible! It will give your roof a longer lifespan, meaning you won’t need to replace it too soon because of the rot algae can cause.