Holding the Line: Edge Restraints and the Art of Durable Paver Design

Part 3 of the “Designing with Strength” series for landscape architects and designers

Previous post in this series: Building from the Ground Up: Installation and Base Preparation for 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.

This is a simple illustration of a plastic edge restraint. It should NOT be considered a guide to installation!

Few things in a landscape are as understated—or as essential—as a well-placed paver edge restraint. Beneath every beautifully patterned hardscape lies an unspoken truth: without containment, even the best-laid field will wander.

As both a landscape architect and a former hardscape contractor who spent years in the field as an ICPI-certified installer, I’ve seen firsthand how the integrity of a pavement depends as much on its edge as on its base. Good design might define the space—but a good edge keeps it that way.

---

Why Edge Restraints Matter

Every interlocking paver system relies on three fundamentals: a properly compacted base, a uniform bedding layer, and a secure edge restraint. Remove any one of them, and the pavement begins to fail.

The edge restraint is the boundary that keeps order—the quiet structure that resists the outward forces of load, temperature, and time. When installed correctly, it maintains the tight interlock that defines the entire system. In many ways, the edge is not just the perimeter—it’s the promise of longevity.

---

Concrete Edge Restraints: The Structural Standard

Concrete haunching remains the benchmark for structural reliability, particularly under vehicular or commercial loads. Installed on the compacted aggregate base (not on bedding sand), it’s typically 4 inches wide by 6 inches deep and slopes slightly away from the paver field to promote drainage.

Advantages

• Exceptional strength and permanence

• Cost-effective and widely available

• Excellent for driveways, roads, and high-use plazas

Limitations

• More labor-intensive

• Less adaptable to tight curves

• Can trap moisture if improperly graded

Designer’s PerspectiveThink of the concrete haunch as the unseen curb of your composition—strong, predictable, and essential when performance matters more than flexibility.

Metal Edge Restraints: Precision with a Modern Voice

Aluminum and galvanized steel edge restraints lend a sleek, contemporary finish to a landscape. Their low profile and sharp definition make them ideal for minimalist detailing.

Advantages

• Clean, modern aesthetic

• Fast installation and minimal visual impact

• Long-lasting when corrosion-protected

Limitations

• Not suitable for heavy vehicular use

• Steel can corrode in coastal or high-moisture environments

• Slightly higher material cost

Designer’s PerspectiveMetal edging works beautifully where design precision is part of the visual narrative—urban plazas, courtyards, and structured residential landscapes where restraint supports the design intent rather than competing with it.

Plastic Edge Restraints: Flexible, Reliable, and Affordable

Flexible PVC or HDPE edge restraints remain a go-to solution for many residential and pedestrian applications. Properly anchored on the base and not in the sand bed, they provide reliable containment for patios and walkways.

Advantages

• Highly flexible—ideal for curves and organic shapes

• Easy and quick to install

• Resistant to moisture, rot, and corrosion

• Economical

Limitations

• Not appropriate for vehicular or heavy-use pavements

• Can degrade from prolonged UV exposure

• Requires proper anchoring (stakes every 8–10 inches)

Designer’s PerspectivePlastic edging is often underestimated, but when installed correctly on a well-compacted base, it performs admirably. It’s the practical edge solution for small-scale, pedestrian environments where flexibility meets efficiency.

Stone or Precast Edging: The Classical Frame

Stone or precast concrete edging adds weight, texture, and permanence to the perimeter of a pavement. It’s both functional and expressive—serving as the literal and visual frame of the hardscape.

Advantages

• Visually substantial and durable

• Complements natural materials and historic settings

• Adds architectural richness

Limitations

• Heavier, more expensive, and labor-intensive

• Limited flexibility for curved layouts

Designer’s PerspectiveThis is the edge for legacy landscapes—formal gardens, civic plazas, or institutional grounds—where authenticity and permanence take precedence over speed and cost.

Soldier Course with Concealed Backing: Structure as Design

When the border becomes part of the composition, a soldier or sailor course (pavers set perpendicular or parallel to the field) creates a seamless transition between function and form. A concealed concrete haunch behind it ensures stability.

Advantages

• Visually unified edge treatment

• Provides good structural restraint when backed

• Allows for creative color and pattern contrasts

Limitations

• More installation precision required

• Requires continuous, concealed backing

Designer’s PerspectiveAn integrated soldier course isn’t just an edge—it’s part of the design language. Use it where the border defines not only the structure but also the rhythm and flow of the space.

---

Choosing the Right Edge

Designers should select an edge restraint that balances load, layout, and longevity:

Application	Recommended Restraint	Key Benefit
Residential Patio or Walkway	Plastic Edge	Flexible and economical
Driveway or Heavy Use Area	Concrete Haunch	Structural strength
Modern Plaza / Courtyard	Aluminum or Steel	Clean architectural line
Historic or Formal Landscape	Stone / Precast	Visual permanence
Integrated Design Edge	Soldier Course	Unified aesthetic restraint

---

Installation Essentials

Regardless of material, certain fundamentals apply across every system:

• Place the restraint on the compacted base, not on bedding sand.

• Extend the base beyond the restraint by a distance equal to the base thickness.

• Maintain a 1–2% outward slope for drainage.

• Anchor spikes or stakes every 8–10 inches, closer along curves.

• Compact the base and bedding thoroughly before and after edge installation.

These details might not appear in the final renderings, but they determine how that rendering performs in the real world.

---

Final Thoughts: The Discipline of Design

Edge restraints aren’t glamorous, but they are the guardians of design intent. They preserve alignment, protect interlock, and maintain the form we worked so hard to define.

Good landscape architecture depends on the union of concept and craft. Whether that craft happens in CAD or on-site with a hand tamper, the principle remains: design integrity begins—and endures—at the edge.

Previous Article: Building from the Ground Up: Installation and Base Preparation for Interlocking Pavers

Next in the Series: Locking It In: Polymeric Sand and Joint Stabilization for Interlocking Pavers

For more technical guidance and specification standards, refer to the Concrete Masonry & Hardscape Association (CMHA), formerly the Interlocking Concrete Pavement Institute (ICPI). Their Tech Spec 3: Edge Restraints for Interlocking Concrete Pavements remains the definitive resource for design and installation details.