Hadeka Stone Corporation

VT: 802.468.5472 | NY: 518.282.9605

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Yorkmont Slate Survives The Ages

A slate roof, over the long term, is one of the most cost-efficient investments that a building owner can make. A slate roof will outlast several generations of other roofing materials and the roofing slate produced in Vermont and New York will last an average of 75 - 100 years and requires little, if any maintenance over its entire life.

Roofing slates have specific weathering characteristics.  Some slate is referred to as “unfading” in that the basic color will remain consistent after many years of exposure. The “semi weathering” and “weathering” slates will fade to usually shades of brown after a period of exterior use. The weathering characteristics do not impact  the integrity or life of the roofing slate.

Roofing slate is sold by the square. A square of roofing slate is the specific quantity  to cover 100 square feet of standard roofing surface when installed with a 3-inch head lap.

We manufacture ASTM Grade S-1 (highest quality) roofing slate. 

ASTM Test Results: Red Slate

Water Absorption, C121-90       0.143%      ASTM max for S1 slate is 0.25%

Modulus of Rupture, C120/C120M-09

Across Grain:  13401 psi           ASTM min. for Class I ext. slate 9000 psi     
Along Grain:   10781 psi           ASTM min. for Class I ext. slate 7200 psi

Weather Resistance, C217-94   0.0003 in.   ASTM max. for S1 slate is 0.002 in.

For additional test results on our other roofing products please call toll-free at 1.877.HADEKAS.



Hadeka Stone Corp. has distinguished itself as a socially responsible and environmentally considerate stone manufacturing operation. Our waste management strategy involves continually looking for new markets for tailings and recycling of concrete and asphalt.

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Product Lines

  • Yorkmont Slate
  • Northeast Fast-Dry
  • Red Diamond Clay
  • Yorkmont Landscape Stone