StainGuard Plus™ 
Time-Release Technology

Help protect your roof from unsightly stains.

StainGuard Plus™
New Time Release Technology provides long-lasting algae fighting power.
Time Release Technology
Specially engineered capsules infused with copper microsites consistently release algae-fighting copper over time.
25 Year Limited Warranty
Backed by 25 -year limited warranty against blue-green algae discoloration.
What’s causing those dark streaks?
In virtually any residential neighborhood in the U.S. or Canada, there’s a chance you’ll see at least one roof stained with black or dark brown streaks. Many homeowners mistake these stains for mold, mildew, moss, or even tree sap.

They’re often actually caused by tiny bacteria commonly called blue green algae (scientific name: Gloeocapsa magma). When you see the dark stains, you’re looking not at the algae, but at the hard, dark coating it generates to protect itself from damaging UV rays.

Gloeocapsa magma travels on the wind — which means if your neighbor has it, your roof has probably been exposed as well. It thrives in moist environments and can get nutrients from dust in the air. It’s more likely to appear on the north and west sides of the house. According to the Asphalt Roofing Manufacturers Association (ARMA), there’s no scientific evidence that algae is damaging to asphalt shingles. But it can definitely affect the appearance and resale value of your home.

That’s the bad news. The good news is that Gloeocapsa magma is both treatable and, with the right shingle technology, preventable.

Algae fighting has come of age with StainGuard™ Time Release Technology
Certain metal ions, like copper and zinc, can help reduce algae growth. That’s why you’ll sometimes see copper or zinc strips installed at the roof ridge on older homes.

Another method is to incorporate copper-containing granules on the surface of the shingle. In fact, traditional algae-prevention shingles include granules that contain a layer of algae-fighting copper. And that works well — for a while. But eventually, the granules degrade and become less effective.

That’s why GAF developed StainGuard Plus™ Time Release Algae-Fighting Technology. Unlike older technology that concentrates the copper in a layer, StainGuard® Plus™ uses specially engineered capsules infused throughout with thousands of copper microsites. Copper remains within reach, ready to be activated to help protect your roof against blue-green algae stains.

Roofing shingles featuring StainGuard® Plus™ Technology

*StainGuard Plus™ algae protection is available only on shingles sold in packages bearing the StainGuard Plus™ logo. Products with StainGuard Plus™ algae protection are covered by a 25-year limited warranty against blue-green algae discoloration. See GAF Shingle & Accessory Limited Warranty for complete coverage and restrictions




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At GAF, we train and test thousands of roofers make sure they're appropriately licensed (in states where licensing is required) and insured so they can offer our best warranties.*






*Contractors enrolled in GAF certification programs are not employees or agents of GAF, and GAF does not control or otherwise supervise these independent businesses. Contractors may have agreed that they will use GAF roofing products, and may receive benefits, such as loyalty rewards points and discounts on marketing tools from GAF for participating in the program.