Why Specify a Cast Stone Institute Certified Plant?
Learn What it Takes to be CSI Certified
Prior to admission, each potential Producer Member must submit to a rigorous examination of product quality, safety, testing, including freeze thaw, meticulous record keeping and financial stability. Once certified, they undergo the recertification process every other year with unannounced inspections and test data reporting every six months in addition to numerous other requirements.
Cast Stone Specification
Every CSI Certified Producer meets and exceeds the requirements of ASTM C1364 — the industry standard for architectural cast stone. Certification goes beyond just meeting the minimum: our members follow strict production, testing, and documentation protocols to ensure the highest quality, consistency, and performance on every project.
When you specify a CSI Certified Producer, you’re getting more than compliance — you’re getting trusted excellence backed by third-party oversight.
10 Year Warranty
Every CSI Certified Producer Member stands behind their work with a 10-Year Limited Product Warranty — a commitment to sustainability, durability, and lasting performance that sets CSI members apart.
Testing Requirements
CSI Certified Producers are required to test for compressive strength (ASTM C1194) and absorption (ASTM C1195) for every 500 cubic feet of cast stone produced, for each production method used at their facility. Test data is submitted to the CSI office each March and September, and must be independently verified by a qualified laboratory at least once every six months. Freeze-thaw durability testing (ASTM C666) and linear shrinkage testing (ASTM C426) are also required for each production method regardless of quantity produced.
Plant Inspection Requirements
What truly sets CSI Certified Producers apart is a rigorous 86-step plant certification process — one of the most comprehensive in the construction industry. Every certified facility is evaluated across six critical areas:
Product Quality Control — compressive strength and absorption testing
Safety — full OSHA compliance
Product Consistency — dimension, color, texture, and tolerances
Recordkeeping — meticulous documentation of production and testing
Housekeeping — facility standards that reflect quality operations
Recertification — every two years with unannounced inspections to ensure standards are maintained
Simply stating that a plant complies with CSI certification guidelines is not enough. Certification must be verified, documented, and renewed — ensuring that every CSI Certified Producer is consistently delivering the highest quality cast stone on every project.