A concrete edging stone is a mini kerb. Whereas kerbs are used for roads, edgings are used for driveways and paths. Usually, one edge has a rounded “bull nosed” edge which softens the look of the stone and also protects car tyres when used on a driveway. This project deals with straight, concrete edging stones. There are many types of edging stones for varying uses around the garden. Some just sit in soil, some on a mortar bed and some need concreting. The principle is the same.
Edging stones are used to stop the base spreading as weight is applied to it and as such must be laid in a strong mix of concrete themselves.
A couple of inches (50-75mm) of concrete mixed at 6 to 1 (see our mixing concrete project) is laid along the line you would like the edgings to follow. An edging stone is laid at one end and tapped to level, usually with a paving mallet or the handle of a lump, or club, hammer. A string line is then attached to the back edge of the stone and run out to the other end of the drive or path where another edging stone is positioned in the same way. This stone will probably be temporary as it may have to be replaced by a cut stone depending on the length of the path or drive.
Remember to take into account the slope of the drive, and if using edgings on both sides, use a long piece of timber to level across. If the distance is too great, transfer the level using pegs banged into the ground.
Once the two end stones are in and the string line is in position you can lay the rest of the edgings. Tap each one down into the concrete butting one up against the next one. There is no need for a joint. You may need to cut one or two edgings to fit the length of the drive or path and this can be done with an angle grinder as shown below. Make sure you hire or buy stone cutting disks as metal cutting disks will not get through stone or concrete.
When all the edging stones are in position concrete is placed at the back and front of them. Almost always the main pressure against the edging stone is from the front so most of the concrete needs to be at the back as you will probably have a sub base of some kind at the front. Remember to leave enough depth for a little soil if you are reinstating turf etc behind the stones and compact the concrete well using a flat piece of timber or preferably a wooden or plastic plastering float. Angle the concrete away from the stone so water does not sit on the top of the concrete.