California Slate Company

California Slate Company Premium natural slate roofing solutions. Traditional & lightweight systems built for beauty, durability, and sustainability. Based in California.

For anyone bidding re-roofs: Vermont Gray-Black, new in SLATE2 only.550 lbs per square against 960 for comparable full-w...
09/22/2026

For anyone bidding re-roofs: Vermont Gray-Black, new in SLATE2 only.

550 lbs per square against 960 for comparable full-weight Vermont slate.

On a re-roof over existing framing, that difference usually means no structural reinforcement, which takes an engineer's letter, a schedule delay and a line item straight out of your bid. Easier to sell, faster to close, fewer surprises once you are on the roof.

1/4" to 3/8". ASTM C406 S1. 50-year system warranty. Installs with the SLATE2 interlayment system.

(Read full details here: https://www.californiaslatecompany.com/post/vermont-gray-black-lightweight-vermont-slate)

We supply; we do not install, so we are not competing with you, and we will refer homeowners who need a qualified slate roofer.

Samples, quantities, and freight quotes:
888.994.0842
www.calslate.com


"Your house can't take a slate roof."A lot of homeowners have heard that. It used to be true more often than it is now.M...
09/15/2026

"Your house can't take a slate roof."

A lot of homeowners have heard that. It used to be true more often than it is now.

Meet Vermont Gray-Black: real Vermont slate, quarried, not manufactured, in that classic deep gray you picture on a house built to last. The difference is weight. It comes in at about 43% lighter than traditional slate, which for most homes means no structural work, no reinforcement, no engineer.

A slate roof lasts 100 to 200 years. Most roofs last 20. You are not buying a roof, you are ending the conversation about roofs.

(Read full details here: https://www.californiaslatecompany.com/post/vermont-gray-black-lightweight-vermont-slate)

Order a sample and see it in daylight. Screens lie about color.

www.calslate.com


New in the line: Vermont Gray-Black, available exclusively in SLATE2.ASTM C406 S1 grade. 1/4" to 3/8". 550 lbs per squar...
09/09/2026

New in the line: Vermont Gray-Black, available exclusively in SLATE2.

ASTM C406 S1 grade. 1/4" to 3/8". 550 lbs per square.

That last number is the one that matters. Comparable full-weight Vermont slate runs 960 lbs per square. At 43% less load, the structural reinforcement conversation usually ends before it starts, which, in adaptive reuse and historic work, is often the difference between specifying slate and specifying something that imitates it.

(Read full details here: https://www.californiaslatecompany.com/post/vermont-gray-black-lightweight-vermont-slate)

Appearance is uniform medium-to-dark gray with subtle black linear markings. We will also tell you what most suppliers will not: roughly 4-6% of these slates show slight weathering after 12 to 18 months. It reads as character; it is predictable, and you should know it before you put it in a spec rather than after.

Material service life 100-200 years. 50-year system warranty.

https://www.californiaslatecompany.com/slate2


09/05/2026

Labor Day is here, and at California Slate we’re celebrating the folks who turn heavy slate into beautiful, weatherproof roofs. Today’s the perfect time to appreciate the sweat, the skill, and the perfectly placed shingles—because good roofing never takes the day off. Enjoy the break.

www.Calslate.com

Here's the part most homeowners never calculate: over 100 years, an asphalt roof gets replaced 4–5 times. A natural slat...
07/08/2026

Here's the part most homeowners never calculate: over 100 years, an asphalt roof gets replaced 4–5 times. A natural slate roof? Once. 🪨

Factor in lifespan, fire resistance, and home value, and "expensive" starts to look a lot like "efficient." 🔗 See why slate pays off: https://www.californiaslatecompany.com/post/is-a-slate-roof-worth-it-cost-vs-lifetime-value



LinkedIn
One natural slate roof can outlast four or five asphalt replacements. When durability, fire resistance, and resale value enter the equation, the long-term math favors slate. We break it down in our latest article. [blog link]

07/04/2026

Happy 4th of July from California Slate.

Today we celebrate the spirit of independence, community, and pride in what we build together. May your day be filled with family, reflection, and moments that last long after the fireworks. Thank you for being part of our story.

www.CalSlate.com

Build With Materials You Can TrustSpecifications matter — especially when you’re designing roofing systems that must las...
05/27/2026

Build With Materials You Can Trust

Specifications matter — especially when you’re designing roofing systems that must last generations. California Slate provides architects with true S-1 Grade natural slate backed by certified testing, structural documentation, WUI compliance, and performance data you can rely on

From submittals to installation details, we support your team with the right information at every stage of the process. Clear specs mean fewer surprises in the field — and stronger outcomes for your clients.

Explore specs + certifications →
Read the full article here
https://www.californiaslatecompany.com/post/specifying-with-confidence-why-architects-rely-on-certified-s-1-grade-slate
🔗 www.californiaslatecompany.com/testing-certifications


Recommended @ Mentions:
The American Institute of Architects CSI Construction, Inc. Building Design+Construction

Build With ConfidenceSpecifying slate shouldn’t be complicated. Our architectural resources include ASTM data, installat...
05/25/2026

Build With Confidence

Specifying slate shouldn’t be complicated. Our architectural resources include ASTM data, installation guidelines, CAD details, and product specs — all curated to streamline your workflow and give your clients better outcomes.

Full details here:
https://www.californiaslatecompany.com/post/the-architect-s-guide-to-specifying-slate-roofing

Access everything here:
www.californiaslatecompany.com/testing-certifications
AIA California CSI Construction, Inc. Building Enclosure

Design Without LimitsModern architecture demands performance, precision, and timeless materials. Natural slate checks ev...
05/20/2026

Design Without Limits

Modern architecture demands performance, precision, and timeless materials. Natural slate checks every box. California Slate partners with architects to deliver high-grade, design-flexible slate roofing — from modern coastal builds to steep-slope mountain projects.

Architects deserve materials that don’t compromise performance or design intent. California Slate offers true S-1 grade natural slate + lightweight SLATE2™ — engineered for modern build requirements.

Whether you're detailing a contemporary residence or restoring a historic property, our team supports you with specs, samples, and technical guidance.

Read full info here:
https://www.californiaslatecompany.com/post/designing-without-limits-why-slate-belongs-in-modern
AIA National Construction Specifications Institute

Samples, specs, and one-on-one support available.
📐 Explore architectural resources: www.californiaslatecompany.com

The American Institute of Architects American Institute of Architects Orange County - Associates ArchDaily

Address

344 Market Street
San Francisco, CA
94114

Telephone

+18889940842

Website

Alerts

Be the first to know and let us send you an email when California Slate Company posts news and promotions. Your email address will not be used for any other purpose, and you can unsubscribe at any time.

Contact The Business

Send a message to California Slate Company:

Shortcuts

Featured

Share

Category