The ASTM or American Society for Testing and Materials.

Roofing slate standards are set by the ASTM International, an independent standards organization. Since 1957 the ASTM has established a consensus for building material standards. The ASTM C406 is the world-wide “Standard Specification for Roofing Slate”. It addresses material characteristics and physical properties of the roofing slate, among other things that are important for testing. There are three tests used for grading slate:

• C121 – Water Absorption of Slate
• C217 – Weather Resistance of Slate
• C120 – Flexure Testing of Slate

Based on these three tests, the ASTM can specify which of the following three grades the roofing slate falls into  (dependent on geographic location and environmental exposure):

• S1 Grade Slate –  expected service life of 75+ years
• S2 Grade Slate –  expected service life of 40 to 75 years
• S3 Grade Slate –  expected service life of 20 to 40 years

SlateTec Lightweight Slate Roofs use only high quality S1 Grade roofing slate. SlateTec weighs roughly 40% less than traditionally installed slate. It retains all the essential qualities that make natural slate the best possible option for any roof.  Our design team can accommodate any custom or standard roofing project and help you choose from the many options available to help build the perfect roof for you. Please call us anytime.