Paver edging options: which edge restraint holds best?

Why pavers need an edge at all

Sand-set pavers hold together by friction and interlock. Push on the edge with nothing behind it and the units start to spread. CMHA, the concrete paver industry association, calls edge restraints "an essential component" that hold pavers tightly together and keep them from spreading under traffic^[1]. BIA, the brick industry association, says the same for clay pavers^[2].

HomeGuide puts it in plain terms: without edging, pavers slowly shift into the surrounding ground and gaps open around the perimeter^[4]. Edging is a small part of the cost. HomeGuide counts edging or a concrete bond beam at about $0.10 to $0.20 per square foot of patio, inside a base materials total of $1.40 to $2.20 per square foot^[4].

The options compared

Edge restraint	Good for	Notes from industry guides
Plastic edging made for pavers	Patios, walks, light residential use[1]	Quick to install, will not rust or rot; must be spiked well into the compacted base[1]
Aluminum edging	Patios, walks; heavier gauges for vehicles[1]	Spike into the base or fasten to a concrete base; use the thickest edging under vehicle traffic[1]
Steel edging or angle	Rigid (concrete) bases only[1]	Paint or galvanize to avoid rust stains; CMHA says not to use steel on flexible gravel bases[1]
Precast concrete or cut stone	Full-depth units run the depth of the base; partial-depth units suit residential and light commercial use[1]	Partial-depth units are spiked to the base, typically with 3/8 inch spikes[1]
Poured concrete curb	Driveways and anything with vehicle traffic[1][2]	Side should extend well below the bedding sand; compact well next to it[1]
Submerged concrete edge with pavers mortared on top	Residential driveways and low-volume streets[1]	Minimum 8 by 8 inch cross section[1]
Troweled concrete edge (a "haunch")	Only where the ground does not freeze; pedestrian and light driveways[1]	At least 4 inches wide, covering two-thirds of the edge paver's side, with steel reinforcing[1]
Timber	Not recommended	Warps and eventually rots[1]
Flat garden edging	Not acceptable	Too little lateral support[1]
Soil backfill	Never	Not a restraint at all[1]

For clay brick pavers, BIA's guidance lines up: concrete or stone curbs, steel angles anchored to concrete, or a traffic-rated proprietary system for anything with cars, and any of those or spiked plastic or metal systems for patios and walks^[2].

Install details that decide whether edging works

Most edging failures trace to how it was set, not the product. From CMHA's edge restraint guide^[1]:

• Extend the base past the edging. The base should reach beyond the restraint at least as far as the base is thick. A 6 inch base should extend at least 6 inches past the spikes.
• Spike into the base, never into soil. Spikes should go well into the compacted aggregate. They do not need to go through the bottom of the base.
• Never set edging on the bedding sand. It must sit on the compacted base.
• Give the pavers a real wall. At least 1 inch of vertical restraining surface should touch the side of the edge paver. BIA also says the face should be vertical, not sloped^[2].
• Set the height right. Sand-set pavers may finish about 1/4 inch above the top of the restraint to allow minor settling and drainage.
• Fill gaps properly. Gaps over 3/8 inch get cut pavers. Smaller gaps get the coarsest sand or aggregate that fits. Under vehicles, cut pavers should be no smaller than one third of a whole unit.
• Stop sand loss. Where bedding sand could wash out under or between edging pieces, a 12 inch wide strip of geotextile along the base, turned up the side of the restraint, is recommended.

L-shaped metal edging adds stability^[1]. On curves, CMHA describes laying the pavers past the planned edge, marking and cutting them, then setting the edging against the cut line^[1].

Driveways need more than patio edging

Vehicles push sideways when they turn and brake. For driveways:

• CMHA recommends the thickest aluminum or steel edging for vehicle traffic and lists submerged concrete edges sized at least 8 by 8 inches for residential driveways^[1].
• BIA recommends concrete or stone curbs, or steel angles anchored to a concrete base or foundation, for any clay paver area with regular vehicle traffic^[2].
• CMHA calls for a residential driveway base of at least 6 inches on well-drained soil, more on weak or wet soil and in cold climates^[3]. The edge restraint has to sit on that same base.

Myth: "A concrete haunch works anywhere"

Many crews trowel a wedge of concrete against the outside of the edge pavers. CMHA allows a troweled, reinforced concrete edge only in areas where the ground does not freeze, only for pedestrian and light residential driveway loads, and only if it is at least 4 inches wide and covers at least two-thirds of the side of the edge pavers and bedding sand^[1]. BIA is more cautious and says concrete backing poured to restrain edge pavers "may not be effective over the long term"^[2].

So in Ohio, Illinois and other freezing climates, ask for a manufactured restraint or a full concrete curb instead. In parts of Texas without hard freezes, a properly built haunch may be acceptable for a patio, but ask the installer to show the width, height and reinforcement in the bid.

Signs your edging has failed

• A gap opening between the outer row of pavers and the lawn or bed.
• Edge pavers tipping outward or sitting lower than the field.
• Joint lines that drift or open up near the edge.
• Spikes pulled up, or edging that moves when you push it with your foot.

Fixing it usually means lifting the edge rows, rebuilding the base where it was short, setting new restraint on the base, and relaying the same pavers. See fixing sunken pavers.

When to call a pro

• If edge pavers on a driveway are spreading, since the restraint and base may both need upgrading for vehicle loads.
• If the edge sits next to a slope, retaining wall or pool, where failure can undermine more than the patio.
• If you are unsure whether your base extends past the edging, a contractor can dig a test spot and check.
• Before building in a freezing climate with a concrete haunch, ask a contractor in your area about a manufactured restraint instead.