Across North America, climates make conditions just right to give roofs a distinctive dark "watermark" stain—a telltale sign of blue-green algae growth.
Although the blue-green algae won't damage your roof, it can leave potential buyers thinking that a roof is old or damaged, which can reduce the home's value. Roof algae removal can be difficult without damaging shingles, so expect homeowners to leave it to the professionals.
Blue-green algae is a cyanobacterium called Gloeocapsa magma that travels through the air. It is more prevalent in warm, wet climates. Because it travels easily, the stains often affect whole neighborhoods. In an effort to shield themselves from the sun, the blue-green algae develop a brownish-black shell that causes roofs to appear dark and stained. Unlike moss or tree droppings, which typically produce only localized discoloration, algae discoloration may be uniform or appear as streaks on the roof.
In a 2021 GAF survey* of 500 homeowners, 87% said they viewed protecting their roof from blue-green algae as very or extremely important. In response, GAF has developed industry-leading technology to provide homeowners with a product that helps protect combat the problem. Let's walk through everything contractors need to effectively sell GAF Time-Release Algae-Fighting Technology.
Benefits of GAF Time-Release Algae-Fighting Technology
For years, shingle manufacturers have added copper to roof granules to help prevent blue-green algae growth. As the roof dampens during rainfall, the copper leaches out of the granules and helps prevent the bacteria's growth. But, as the copper is used up, the protection wanes. That's why GAF developed its proprietary technology that infuses special capsules with thousands of copper microsites that provide controlled release of protective copper: GAF TIme-Release Algae-Fighting Technology.
25- and 30-Year Warranties Against Blue-Green Algae Discoloration
GAF Time-Release Algae-Fighting Technology allows contractors to offer homeowners strong algae protection limited warranties on a variety of shingles including architectural, designer, ridge caps, and visible starter strips. Below are the two warranties that are offered:
25-year StainGuard Plus™ Algae Protection Limited Warranty**—offers 25 year protection against blue-green algae discoloration; available on GAF Timberline HDZ® Shingles, Designer Shingles, Ridge cap Shingles, and more.
The new 30-year StainGuard Plus PRO™ Algae Protection Limited Warranty***—this new limited warranty is only available on the new GAF TImberline ® UHDZ™ Shingles. GAF adds 10% more GAF Time-Release Algae-Fighting Technology than it does on StainGuard Plus™-labeled shingles, allowing them to offer 30 years of limited warranty coverage on these shingles.
Customer Talking Points
These talking points can be used to educate your customers about blue-green roof algae and help them decide if products with GAF Time-Release Algae-Fighting Technology are right for their roof.
Many homes in North America suffer from blue-green algae discoloration. The issue is most prevalent in warm and wet climates.
Although blue-green algae won't damage the roof or shingles, the resulting dark stains can affect home resale values.
The dark staining caused by blue-green algae growth may reduce the effectiveness of cool roofs.
Blue-green algae-stained roofs can be cleaned with a bleach solution to help lighten the stain and prevent the algae's spread to other roofs. The Asphalt Roofing Manufacturers Association (ARMA) recommends using a solution of equal parts chlorine bleach and water but advises that directions for mixing them may vary depending on the shingle manufacturer and the amount of discoloration. The group suggests getting the approval of the manufacturer before trying other cleaning chemicals or methods.
Blue-green roof algae removal is best done by a roofing professional to avoid shingle damage.
Regular maintenance, gutter cleaning, and tree trimming can help reduce blue-green algae growth.
ARMA does not recommend adding zinc or copper strips to an existing roof. Doing so requires breaking the sealant bond to place the strips. If not installed correctly this may leave exposed nails resulting in wind damage and leaks.
Learn more about the algae-fighting products GAF has available for your customers at GAF Time-Release Algae-Fighting Technology or reach out to your Territory Manager for in-depth knowledge about what works best for your region.
*Based on a 2021 survey commissioned by GAF of 500 homeowners in areas with moderate to high amounts of blue-green algae.
**25-year StainGuard Plus™ Algae Protection Limited Warranty against blue-green algae discoloration is available only on products sold in packages bearing the StainGuard Plus™ logo.
***30-yearStainGuard Plus PRO™ Algae Protection Limited Warranty against blue-green algae discoloration is available only on products sold in packages bearing the StainGuard Plus PRO™ logo. See the GAF Shingle & Accessory Limited Warranty for complete coverage and restrictions.
