CertainTeed's Carriage House® UL 2218 Class 4 Impact Resistant and Algae Resistant shingles have been painstakingly designed to evoke a unique, hand-crafted look. Equal measures of craftsmanship and architectural creativity are at play in this shingle. With cut-away corners and wide, dark shadow lines, Carriage House creates a one-of-a-kind look of scalloped-edge natural slate—offering the perfect roofline for your home and the level of protection provided by Carriage House's super-heavyweight construction makes for a perfect pitch. These shingles are made from high-quality materials that are specifically designed to withstand environmental factors that can impact the appearance and performance of a roof. One of the key features of CertainTeed's Carriage House shingles is their Underwriters Laboratories (UL) classification. This certification ensures that the shingles meet strict industry standards for safety, quality, and performance. The UL classification is a third-party certification that provides homeowners with peace of mind knowing tha...See Moret their roofing investment is safe and reliable. Carriage House shingles are also backed by a 30-year algae resistance warranty, ensuring that the shingles will remain resistant to algae growth for three decades. The warranty provides homeowners with confidence in their investment and guarantees that their roofing will maintain its appearance and performance for an extended period. In terms of cost-effectiveness, CertainTeed's Carriage House shingles are a great investment for homeowners. The durability and longevity of these shingles mean that they require less maintenance and fewer repairs over time, which can save homeowners money in the long run. Overall, CertainTeed's Carriage House shingles are an excellent roofing option for homeowners looking for a high-quality, reliable, and durable solution that can resist unsightly algae growth. The UL classification ensures that these shingles meet strict industry standards, and the 30-year algae resistance warranty provides homeowners with confidence in their roofing investment. See Less