Hardscape: Unit Paver and Edging Installation

Hardscape: Unit Paver and Edging Installation

A well-built paver walkway lasts decades when every layer beneath the surface is built correctly. This lesson walks through the full process — from breaking ground to the final sweep of polymeric sand — and explains why each step matters for drainage, stability, and a surface that meets professional standards.

Why Proper Base Construction Matters

Pavers are a flexible pavement system. Unlike concrete, they do not form a rigid slab; instead, each unit transfers load down through bedding sand and into the compacted aggregate base. If that base is weak or uneven, pavers rock, settle unevenly, and allow water to pond. The base must be compacted in two lifts — never all at once — because a plate compactor cannot achieve uniform density through a thick, loose layer. Compacting in lifts ensures every inch of the base is solid.

Typical base depth for a residential pedestrian walkway is 4–6 inches of crushed angular aggregate (commonly referred to as crusher run or processed gravel). Angular particles lock together under compaction in a way that rounded gravel cannot. Add approximately 1 inch of coarse bedding sand on top of the compacted base, screeded to a consistent depth.

Excavation and Grading

Excavate to a depth equal to the base thickness plus bedding sand thickness plus the paver thickness, plus a small amount to allow the finished surface to sit slightly above grade for positive drainage. Remove all organic material from the subgrade. A plate compactor should make at least two passes over the subgrade before any aggregate is added.

Slope is non-negotiable. A minimum 1% cross-slope (1 inch of drop per 8.3 feet of width) is required so that water sheds off the surface rather than sitting in joints or pooling at the edge. Check slope with a level and a slope gauge at multiple points across the width of the excavation — not just at one end. A slope that is correct at one end but flat or reversed in the middle will cause drainage problems.

Screeding the Bedding Sand

Bedding sand is coarse concrete sand (not fine play sand). Set two screed rails or pipes at the correct elevation on opposite sides of the section. Draw a straight screed board across the rails to create a smooth, consistent surface exactly 1 inch deep. Do not walk on screeded sand after it is set. If you step in it, re-screed that area before setting pavers.

Setting Pavers

Begin at a fixed straight edge — typically an existing structure or a pre-set string line. Lower each paver straight down; do not drag it across the sand, as dragging disturbs the screeded surface. Use a rubber mallet to seat each paver flush with its neighbors. Maintain consistent joint width — commonly 1/16 to 3/16 inch — using spacers as needed. Two common patterns are:

• Running bond: Each paver is offset by half a unit from the row above, similar to brick. Simple and fast.
• Herringbone (45° or 90°): Units are set at an angle, creating a zigzag appearance. Herringbone resists spreading under wheel loads better than running bond and is often specified for driveways.

Check the surface frequently with a straightedge. The finished paver surface must be within 3/16 inch of flat across a 10-foot straightedge. Adjust individual pavers by adding or removing a small amount of sand beneath them, or by tapping with the rubber mallet.

Installing Paver Restraint Edging

Without a restraining edge, pavers gradually migrate outward under foot traffic and freeze-thaw cycles, opening joints and causing the pattern to fail. Install plastic or aluminum paver edging hard against the outside face of the last row of pavers on both sides of the walkway. Drive spikes or stakes through the edging flanges into the compacted base at intervals specified by the manufacturer — typically every 12 inches on straight runs and closer together on curves. The top of the edging should not be visible above the paver surface.

Polymeric Sand and Final Compaction

Sweep dry polymeric joint sand across the surface with a push broom, working it into all joints. Make multiple passes from different directions. Use the plate compactor (with a pad protector over the plate) to vibrate the pavers and settle the sand into the joints. Sweep again, compact again, and repeat until joints are full to within about 1/8 inch of the paver surface. Polymeric sand contains binders that harden when activated with a light mist of water, locking joints against washout and weed intrusion. Follow the product label instructions for moisture activation.

Remove all excess sand from the paver surface before activation — dried polymeric sand residue on the face of pavers is difficult to remove.

Safety

Wear safety glasses at all times when operating the plate compactor or cutting pavers. Hearing protection is required when running the compactor — exposure to engine noise over time causes permanent hearing loss. Gloves protect against abrasion from aggregate and pavers. Knee pads are essential during paver setting; kneeling on aggregate or pavers without protection leads to cumulative joint injury. Never reach under the plate compactor while it is running. Follow lockout/tagout procedures before performing any maintenance on powered equipment: shut the engine off and confirm it cannot restart before clearing jams or adjusting the machine.