FAQs On Interlocking Concrete Paver Installation

The Concrete Masonry & Hardscapes Association's (CMHA) FAQ: Installing Standard Interlocking Concrete Pavers on Open-Graded Aggregates provides a research-backed position for one of the industry’s most popular, and debated, installation methods. 

Developed after three years of rigorous testing and evaluation, this resource provides the definitive guidance professionals can rely on to design, specify and build high-performing open-graded systems.

“Installing pavers over open-graded bases and bedding has grown in popularity for its drainage and frost-heave resisting benefits, but it has also raised questions about long-term performance,” said Rob Bowers, P.Eng., CMHA’s Vice President of Engineering, Hardscapes. “The use of dense graded bases are considered industry best practice, but the recommendations show open-graded base and bedding can be used as an effective alternate for some projects. This FAQ gives contractors and installers the confidence to specify and build with open-graded systems, knowing the guidance is backed by data, testing and long-term performance monitoring.”

What the Research Confirmed

CMHA’s recommendations are based on full-scale load testing and monitored field sections that evaluated:

• Comparative results: Benchmarking open-graded systems against dense-graded bases for strength, settlement and long-term integrity.
• Joint behavior: Documented joint material settlement over the pavement’s life, which will require ongoing monitoring and possible maintenance.
• Hydraulic response: Open-graded aggregates used are minimally affected by water (30–40 percent void space), allowing construction to proceed in wet weather and making it resistant to frost-heave movement.

These findings provide clear, evidence-based direction to the hardscape community, closing long-standing gaps in field guidance and ensuring consistent best practices across the industry.

“With this research complete, CMHA is delivering more than data. We’re providing clear guidance that’s applicable in the field,” said Robert D. Thomas, President and CEO of CMHA. “These recommendations set a common foundation the industry can build on, giving professionals practical, proven guidance they can rely on for every project.

The FAQ is available now on CMHA’s website.