See how copper technology helps resist roof streaks, then compare StainGuard Plus and StainGuard Plus PRO coverage.
Keep the roof looking sharp
Black streaks can change the look of a roof long before you planned a replacement. GAF’s algae protection focuses on discoloration caused by blue-green algae.
Why location matters
Algae occurs across North America. Humid areas face more pressure. The map is a broad illustration, not a prediction for an individual home.
Small granules. A useful job.
GAF’s time-release technology uses specially engineered capsules with copper sites. Copper is released over time to help resist algae discoloration.
| Label | Limited algae coverage |
|---|---|
| StainGuard Plus | 25 years on qualifying labeled products, including AS II |
| StainGuard Plus PRO | 30 years on qualifying Timberline UHDZ |
Coverage is against blue-green algae discoloration and is subject to the written warranty. It is not a promise against every stain, moss or roof problem.
Check these before ordering
Match the package logo to the quoted coverage.
Confirm the exact shingle and ridge-cap products.
Ask for the applicable written warranty.
Keep the original reference
Advanced Algae Protection sell sheet RESGN439 (PDF)
Understand GAF roof warranties
Compare roof options for your home
Illustrations and product photography: GAF. Manufacturer examples are not Barnes N’ Roofs installations. Reviewed September 19, 2026.