Understanding Interlocking Pavers: Choosing the Right Unit for the Job

Part 1 of the “Designing with Strength” series for landscape architects and designers

Previous post in this series: Designing with Strength: A Landscape Architect’s Guide to Interlocking Pavers

Note: This series of articles is intended to provide an introduction to the concepts behind paver design for designers. It is not intended as a 'How To' guide for installers or contractors.

What Paver should you choose?

There’s a reason interlocking pavers have endured for centuries. From Roman roads to modern streetscapes, the principle is the same—individual units that gain strength through connection. Yet in today’s market, designers face an overwhelming variety of choices: concrete, clay, permeable, porcelain, and more.

For landscape architects and designers, selecting the right paver is about more than color and pattern. It’s about function, performance, and longevity—the art of matching design intent to the realities of the ground beneath it.

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The Designer’s Role

Too often, the selection of hardscape materials is delegated to contractors or left to aesthetic preference. But the designer who understands the difference between a 60mm pedestrian paver and an 80mm vehicular one is making more than a technical decision—they’re designing for performance.

A well-chosen paver can control runoff, reduce maintenance, and ensure the pavement performs as intended for decades. A poorly chosen one can fail in its first few years. The difference lies in understanding how material, thickness, texture, and installation method work together.

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Understanding Paver Types

1. Concrete Interlocking Pavers

By far the most common and versatile, concrete interlocking pavers are cast in molds under high pressure, producing consistent units that combine compressive strength with design flexibility.

Advantages

• Available in a wide range of sizes, colors, and finishes

• High compressive strength and low absorption

• Designed for true interlock—load is distributed laterally through joints

Best For: Residential patios, commercial plazas, pedestrian streetscapes, and vehicular pavements up to heavy-duty use (when specified correctly).

2. Clay Brick Pavers

Timeless in character and color stability, clay pavers offer a traditional aesthetic with proven durability. Fired at high temperatures, they resist fading and surface wear, though dimensional variation is greater than in concrete units.

Advantages

• Naturally colored—won’t fade or bleach

• Hard, dense surface that resists abrasion

• Excellent for historic or traditional design contexts

Limitations

• Limited size options and less modular consistency

• More expensive and labor-intensive to cut or fit

Best For: Historic restoration projects, formal landscapes, or any design emphasizing color permanence and natural materiality.

3. Permeable Pavers

A growing segment in both residential and commercial design, permeable interlocking pavers (PICP) allow water to infiltrate through joints or voids into an engineered base below. Properly designed, they reduce runoff, promote infiltration, and help meet stormwater requirements.

Advantages

• Reduces runoff and supports groundwater recharge

• Qualifies for sustainable design credits (LEED, SITES, etc.)

• Can serve as both structure and stormwater management system

Limitations

• Requires specialized base design and maintenance

• Sensitive to sediment clogging if not properly maintained

Best For: Sustainable sites, parking courts, and municipal streets where water management and aesthetics must work together.

4. Specialty and Architectural Units

Manufacturers now offer pavers that mimic stone, wood, or linear plank systems. These products expand design vocabulary but often require special layout or base considerations.

Advantages

• Highly customizable for pattern and proportion

• Can visually bridge architecture and landscape

• Available in permeable and non-permeable options

Best For: Contemporary courtyards, corporate plazas, or custom-designed public spaces where form is as important as function.

5. Porcelain Pavers

A relatively recent addition to the landscape palette, porcelain pavers bring an architectural precision once reserved for interiors into exterior design. Manufactured through high-pressure compaction and high-temperature firing, they produce thin yet remarkably strong units with exceptional dimensional accuracy.

Advantages

• Lightweight and consistent in thickness and size

• Frost-resistant, non-porous, and color-stable

• Wide range of stone, wood, and concrete visual effects

• Excellent slip resistance when properly textured

• Low maintenance and highly stain resistant

Limitations

• Requires a perfectly level, well-compacted base—no forgiveness for unevenness

• Not interlocking in the traditional sense; relies on spacer systems or pedestal supports

• Brittle compared to concrete under point loads

• Higher cost per square foot

Best For: Roof decks, pool terraces, elevated plazas, and contemporary designs seeking crisp lines and minimal maintenance. Porcelain pavers excel where precision and clean detailing matter more than structural interlock.

6. Natural Stone Pavers

While not technically “manufactured,” stone pavers such as granite, limestone, or bluestone deserve mention for their longevity and natural variation.

Advantages

• Unmatched natural beauty and durability

• Ages gracefully with wear and exposure

• High compressive strength

Limitations

• Variable thickness and irregularities increase installation labor

• Typically higher cost and sourcing complexity

• Can spall or flake if not selected for freeze-thaw conditions

Best For: High-end residential landscapes, institutional settings, and civic projects where authenticity, context, and craftsmanship drive the design intent.

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Thickness, Strength, and Use

Paver thickness should match the expected load and base composition. The Concrete Masonry & Hardscape Association (CMHA) recommends the following general guidelines:

Application	Typical Paver Thickness	Example Use
Pedestrian	60 mm (2 ⅜”)	Walkways, patios, courtyards
Light Vehicular	80 mm (3 ⅛”)	Driveways, fire lanes, light streets
Heavy Vehicular	100 mm (4”) or more	Ports, loading zones, municipal streets
Permeable Systems	80–100 mm	Depends on hydraulic design
Porcelain / Stone	20–30 mm	Pedestrian or pedestal-supported applications

Designers should reference ASTM C936 for concrete pavers, ASTM C902 for clay brick, and ASTM C1782 for architectural segmental units. For porcelain, ISO 10545 or manufacturer data sheets are the performance baseline.

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Surface Finishes and Slip Resistance

Texture matters—for aesthetics and safety alike.

• Smooth or Ground Finishes – Refined appearance, ideal for plazas and pedestrian zones; requires slip-resistant treatments when wet.

• Tumbled or Weathered – Soft edges, aged character, and forgiving surfaces for residential applications.

• Textured or Shot-Blasted – Improved traction, ideal for pool decks and public walkways.

• Porcelain Textures – Engineered surface microtextures that achieve slip ratings (DCOF ≥ 0.42 wet).

  
  

Slip resistance is critical where water, grade changes, or high foot traffic occur—especially around pools or public plazas.

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Color, Pattern, and Modularity

Designers now have access to an extraordinary range of modular systems—square, rectangular, plank, hexagonal, and even random-pattern layouts. The goal isn’t simply decoration but direction, rhythm, and proportion.

Color blending defines movement and hierarchy. Contrasts create edges, transitions, or focal zones. For concrete and porcelain units alike, consistent joint alignment and dimensional control define professional quality.

Tip: Always review physical samples in natural daylight and, when possible, observe installed mockups. True color, surface feel, and reflectivity are rarely captured accurately in photos or catalogs.

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Cost and Life-Cycle Perspective

Cost should always be considered through the lens of total performance, not just initial price.

Concrete pavers offer the best cost-to-durability ratio. Clay and stone increase material cost but deliver unmatched longevity. Porcelain carries a higher upfront investment but excels in low-maintenance, contemporary applications.

The designer’s role is to align material life-cycle, aesthetic goals, and maintenance expectations with client priorities.

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Designing with Purpose

Selecting a paver is more than choosing a product—it’s specifying a system. The designer who considers structure, use, and maintenance in material selection helps ensure that their vision holds up under real-world conditions.

Whether it’s the quiet geometry of a plaza, the warmth of a residential courtyard, or the engineered precision of a permeable street, interlocking and modular pavers give designers something rare: form, function, and longevity in one material language.

The right choice begins with understanding how each unit performs—and ends with a design that looks as strong as it is.

Previous Post: Designing with Strength: A Landscape Architect’s Guide to Interlocking Pavers

Next in the Series: Building from the Ground Up: Installation and Base Preparation for Interlocking Pavers

Reference:For technical standards and specifications, refer to the Concrete Masonry &

Hardscape Association (CMHA)—formerly the ICPI—and its resources on material selection, permeable design, and installation practices.