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Laying Concrete Kerbs Along a Driveway

Eugene, an avid self-taught DIYer and engineer, has acquired almost 40 years of experience with power/hand tools, plumbing, and woodwork.

laying-concrete-edging-stones-along-a-driveway

Giving Your Driveway a Crisp, Clean Look

Edging a lawn or driveway gives it it a crisp, clean look and helps the eye to define the boundary between grass, flower beds and the harder look of the concrete, stone or blacktop surface of your drive. There are lots of options including brick and cut stone, but in this article we look at an inexpensive method, using concrete edging stones. These are reasonably easy to install if you have basic DIY skills.

Tools Required for Laying Concrete Edging Kerbs

  1. Shovel for mixing concrete
  2. Cement Mixer (optional) for mixing concrete quicker and more thoroughly
  3. Level for checking edging is plumb
  4. String line and canes, bars, or pegs for supporting line
  5. Mallet or alternatively builder's hammer for tapping stones into place

Materials Required

  1. Kerb stones
  2. Ballast (mixed aggregate) or alternatively small stone and building sand
  3. Portland or flyash cement

As an alternative to making your own concrete, you can buy ready-made drymix.

Overview

Kerbs are supported by a bed of concrete on the underside and haunching or supporting concrete at the rear. Since most of the pressure will be from vehicles and human traffic on the driveway surface, this prevents the stones from being pushed backwards into flowerbeds or the lawn. You can also use concrete at the front for added support or back fill with stone.

I deal with 2 inch by 7 inch edging in this guide. Thicker kerbs with a wider base are normally used for a driveway, but in my case the stones are under bushes at the edge of the drive and unlikely to be driven on. You can also use thin edging stones like these for edging a lawn.

Procedure

Follow these steps to lay your stones

Step 1. Dig a trench

Dig a trench about 8" (200 mm) wide by 7" (175 mm) deep. A 2" to 3" (50 mm to 75 mm) bed of concrete is sufficient for laying light edging kerbs, so that allows 2" to 3" of the edging to project above the surface when placed on top of the bed. However you can adjust the depth of the trench to modify this.

For 2 x 7 edging, dig a trench about 8 inches wide. Adjust the depth so that the underlying bed of concrete exposes the desired amount of kerb above the surface.

For 2 x 7 edging, dig a trench about 8 inches wide. Adjust the depth so that the underlying bed of concrete exposes the desired amount of kerb above the surface.

Step 2. Place a Line the Length of the Trench

A string line acts as a guide for laying stones which are placed so that the top edge of a stone just touches the line along it's whole length. You can make a line with a couple of iron bars, wooden stakes or similar and some string. Tie the line loosely onto each bar so that it can be moved up and down the bars when they're hammered into the ground, rather than pushing the bars in or out of the ground to adjust height.

  1. Push or hammer the first bar into the ground, allowing enough space (2" to 4") at the back for haunching.
  2. If the trench is straight, pull the line tight and hammer the bar at the other end of the line into the ground.
  3. Adjust the height of the line at each end so that it's the desired height above the adjacent ground (e.g. 2"). If the ground is sloped, usually you want the edging stones to follow the slope, so don't level the string.
  4. A line will sag along it's length just like a clothes line or electricity wires. So you need to support it every 6 feet or so with additional bars/pegs. Instead of tying these to the line, just twist the string around each bar. The easiest way to do this is by holding the bar horizontally and wrapping a single turn of string around it. Then twist the bar into a vertical position and push into the ground.
  5. By sighting along the entire length of the line, if necessary adjust the position of the bars from front to back of the trench so that they all line up.
  6. Again by sighting along the line, adjust string up or down on the intermediate pegs so that the line is straight along the full length and doesn't dip on any peg.
Keep the line at the same height above the surface on sloping ground. Use intermediate bars every 6 feet or so to stop it sagging

Keep the line at the same height above the surface on sloping ground. Use intermediate bars every 6 feet or so to stop it sagging

Twist string around intermediate bars. This is an old stair rod.

Twist string around intermediate bars. This is an old stair rod.

laying-concrete-edging-stones-along-a-driveway
laying-concrete-edging-stones-along-a-driveway

Step 3. Mix the Concrete for Bedding the Edging

Use a C30 general purpose mix which is 1 part cement to 4 parts stone and 2 parts sand. (These proportions are by volume not by weight). A single mix with a small cement mixer will produce about a wheel barrow full of concrete, sufficient to bed three, 3 foot/3 m kerbs. Concrete should be mixed stiffly with as little water as possible so that it will support edging stones without being squeezed out from underneath. You can learn how to mix concrete using either of my two guides:

Easy Steps to Making Concrete With a Cement Mixer
8 Steps to Mixing Concrete by Hand

Concrete should be stiff so it doesn't squeeze out from underneath stones and they don't sink into it.

Concrete should be stiff so it doesn't squeeze out from underneath stones and they don't sink into it.

Step 4. Lay a Bed of Concrete

  1. Lay enough concrete in the trench to bed two or three stones and extend it just beyond where the last edging stone in this group will be placed. I've found a garden spade is the most convenient tool, but you can also use a brick laying trowel. As shown in the diagram below, concrete should extend backwards 2" to 4" beyond the the line and stones so that it acts as a base for the haunching and also extend a couple of inches forward into the trench. The depth of the bed should be about 2" to 3" (50 mm to 75 mm).
  2. A short piece of timber (e.g. 1 foot of 2 x 7) the same height as an edging stone, is useful for checking the bed is sufficiently deep to raise a stone up to the string line. Allow an extra inch or so of concrete for sinking after placement and tapping the stone into place.
  3. Smooth off the bed with a piece of timber or trowel to make it roughly level.
Use a shovel, spade or builder's trowel to lay a bed of concrete for several stones.

Use a shovel, spade or builder's trowel to lay a bed of concrete for several stones.

laying-concrete-edging-stones-along-a-driveway
Smooth the bed with a trowel or piece of wood.

Smooth the bed with a trowel or piece of wood.

Using a piece of board or similar as a guide, check the bed is deep enough so that stones can be hammered down about 1/2 to 1" (12 mm to 25 mm) into it.

Using a piece of board or similar as a guide, check the bed is deep enough so that stones can be hammered down about 1/2 to 1" (12 mm to 25 mm) into it.

Step 4. Bed the Edging in the Concrete

  1. Lower a stone gently into place. If concrete is a bit on the soft side, plonking it into place can result in it sinking too much. Ensure it butts tightly up against stones previously laid. Align it so that the back of the stone lines up with the string line.
  2. Using a mallet or the end of the handle of a builder's hammer, tap evenly along the top surface of the stone to bed it into place so that the rear top edge is barely in contact with the line. This can be a bit tricky to judge with curved top edging stones, so use a level from the front, extending back to the line. The level should barely touch the line when a stone is sufficiently bedded down.
  3. If the stone is too low in the concrete bed, lift it back out and add concrete in the low spots. If your mix is too wet, concrete can squeeze out from under a stone, so allow a little extra time for it to stiffen and pull it back into place.
  4. Check the vertical face of the stone is plumb using your level and adjust as necessary.
  5. If you intend to lay further stones later after concrete has set, smooth and taper the bed of concrete that extends beyond the last stone downwards so that it doesn't obstruct laying the next stone.
laying-concrete-edging-stones-along-a-driveway
Extend the bed beyond the end of the last stone you intend to lay so that when you add more bedding concrete, it will merge with it.

Extend the bed beyond the end of the last stone you intend to lay so that when you add more bedding concrete, it will merge with it.

Use a mallet or the handle of a lump hammer to tap stones down into the bed. Don't use the hammer head itself to avoid chipping or cracking concrete. (Sorry this photo is out of sequence taken after haunching added at the front!)

Use a mallet or the handle of a lump hammer to tap stones down into the bed. Don't use the hammer head itself to avoid chipping or cracking concrete. (Sorry this photo is out of sequence taken after haunching added at the front!)

Stones should line up with the line.

Stones should line up with the line.

Step 7. Add Support at the Front and Back

I found that use blobs of concrete at the front and back at each joint helps to keep stones in place until haunching is placed at the back. A pointing trowel is small and useful for doing this. Press the blobs tightly against the stones to give a buttress effect. Continue to lay stones, adding blobs of concrete at each joint.

Use blobs of concrete back and front of stones at joints to keep them in place pre-haunching.

Use blobs of concrete back and front of stones at joints to keep them in place pre-haunching.

laying-concrete-edging-stones-along-a-driveway

Step 8. Place the Haunching Concrete

  • Once concrete is sufficiently stiff, place haunching concrete at the back along the full length of edging. Use a spade, shovel or if the space is narrow, a trowel.
  • In general, haunching should extend at least half way up the back of a stone but you can finish it 1" to 2" (25 mm to 50 mm) below the top edge. The width of the haunching bed should be at least the width of an edging stone. (For my edging project the stones were 2" wide, but I made the haunching bed 4" wide).
  • Pack the haunching with a piece of 2 inch board. You can slope it slightly to aid water run off.
  • Most pressure will come from the front of a driveway as vehicles push gravel downwards and outwards to the side. So haunching is necessary to prevent edging stones from moving backwards relative to each other. You can also add haunching at the front. I just used three blobs per stone, extending up to about 3" below the top of a stone and then back filled in front of the stones with a mixture of sand and small gravel. I can't guarantee this is adequate though, so you can haunch along the full length of stones with concrete to be totally certain they won't move. Front haunching doesn't need to extend up the stones as far as at the back, a couple of inches being adequate.
Haunch and bed dimensions

Haunch and bed dimensions

Bed and Haunching Dimensions

Haunch height

At least half height of stone minium, but ideally up to 2" (50 mm) below top edge of stone

Haunch width

At least width of stone, but ideally about 4" (100 mm)

Bed depth

2" to 3" (50 mm to 75 mm)

Bed width

Haunch width + width of stone + 2" to 3" (50 mm to 75 mm) in front of stone

laying-concrete-edging-stones-along-a-driveway
Pack the concrete with a short length of board.

Pack the concrete with a short length of board.

laying-concrete-edging-stones-along-a-driveway

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2020 Eugene Brennan

Comments

Danny from India on October 20, 2020:

Helpful tips, need to try at my place.

Eugene Brennan (author) from Ireland on October 19, 2020:

Thanks Audrey!

Audrey Hunt from Idyllwild Ca. on October 19, 2020:

Thanks for this tutorial. Helpful photos.