Natural color weathering is due to the mineralogy of the stone and the presence of calcite and iron compounds, primarily fine-grained iron pyrite in the form of limonite. This process can start to become apparent after a few weeks or months.
North Country Semi-Weathering Vermont Black is a premium quality Vermont slate shingle containing shades of gray and black in subtle linear patterns. A percentage of these black slates will weather to tones of brown and buff over time. Drawn from select Vermont quarries, North Country semi weathering Vermont black slate meets or exceeds ASTM requirements as an S-1 rated roofing slate.
When installed with non-corrosive (copper or stainless steel) nails, ASTM S-1 slate should have a service life over 75 years.
North Country Slate is committed to stocking all Vermont and New York produced slates to ensure your project gets started on time. All our American made roofing slate is produced by slate quarries in the “Slate Valley” Vermont and New York region.
North Country Slate offers all the best slate for your roofing project, because they are all produced by select North American quarries and backed by our 75-year warranty. Our slate meets the requirements of an S-1 rated roofing slate under ASTM C406, which is the standard set for breaking load, weather resistance and water absorption.