The Architect’s Guide to Specifying Slate Roofing

Everything you need to know — performance grades, ASTM standards, structure, detailing, and compliance.

Specifying slate roofing involves more than choosing a color. For architects, the right details ensure compliance, longevity, and trouble-free installation.

ASTM C406 S1 is the gold standard — defining absorption, flexural strength, and weather resistance. All California Slate products meet or exceed S1 requirements, giving architects confidence in durability and performance.

Structural load is another consideration. While standard slate performs exceptionally on new construction, remodels and weight-sensitive projects benefit from SLATE2™ — a lightweight natural slate system that delivers premium aesthetics at half the weight.

We provide full technical documentation, including:

• ASTM certifications

• Product test data

• Installation guidelines

• Underlayment recommendations

• Fastener + flashing specs

  
  

Architects rely on us not just for material — but for clarity, support, and confidence throughout design.

Access all technical and certification documents: www.californiaslatecompany.com/testing-certifications