FAQs

Asphalt shingle warranties typically offer very limited coverage for algae resistance, focusing only on specific issues. Manufacturers provide a pro-rated algae-resistant (AR) warranty, but it excludes protection against lichens, moss, mildew, or other vegetation that could cause early shingle failure. The warranty only applies to “Blue-Green” algae, specifically Cyanobacteria Gloeocapsa Magma, leaving other algae types uncovered.

The Asphalt Roofing Manufacturers Association, along with all shingle manufacturers, advises against pressure washing your roof. You might even find manufacturers explicitly stating, “What NOT to do: Do not power wash.”

The reason is that high-pressure washing can harm asphalt shingles by dislodging granules, which can result in premature shingle failure. Additionally, pressure washing offers only a temporary fix, as discoloration is likely to return.

Algae commonly thrives on asphalt shingles because they contain limestone, a key ingredient. Limestone is mainly made of calcium carbonate, which algae use as a food source. When combined with moisture from rain or humidity, it creates an ideal environment for algae to grow.

Algae damages your roof by gradually eating away at the limestone in asphalt shingles, weakening them over time.

Algae also creates a dark stain on your roof, which reduces the shingles’ reflectivity. As more sunlight is absorbed, it increases the heat in your home, driving up cooling costs.

Algae is often just the beginning. It paves the way for fungus, which together form lichens, followed by moss, and eventually other types of vegetation. Unfortunately, these issues are not covered under most manufacturer warranties. By that stage, a roof replacement is usually necessary.

Copper Moss Boss strips are made from pure antimicrobial-grade copper, with a purity range of 95.2% to 99.99%. Copper is classified as a “non-corroding metal” and is naturally resistant to corrosion. Because manufacturers typically require non-corroding metals like copper for roof flashings and valleys, using Copper Moss Boss strips will not void your roof warranty. Be sure to verify with your manufacturer for confirmation.

If your shingles have an algae-resistant warranty, they likely contain copper granules embedded in the surface during the manufacturing process.