Concrete edging, sometimes referred to as a concrete toe, can add strength and durability to a patio made of pavers. This type of edging is often chosen for projects because of its easy installation and relatively low cost.
Extrend the area of the base of the patio. This is best done at the beginning of the patio project by making the base (including the sand below the pavers) wide enough so that it measures an additional 15 cm (6 inches) beyond the planned size of the patio on all sides. The sand should be screeded, level, and undisturbed.
Lay all your pavers as you normally would according to your patio plan. Take a flat shovel and dig a trench for the concrete toe. Start at a point about 10 cm (4 inches) away from the edge of the border stones and dig down to a depth of about 10 cm (4 inches). To cut the edge of the trench near the stones, use the flat shovel edge and dig straight down the edge of the stone, being careful not to disturb the stone or base underneath.
Mix a batch of concrete. Shovel concrete into the trench. Using the mason's trowel, push firmly to pack the concrete against the bottom of the trench and the bottom edge of the stone. Then smooth more concrete at a 45 degree angle up to a point about halfway up the stone. Allow it to set and dry for at least 48 hours before walking on the edge of the patio.
A set of knee pads will save you from sore knees and be well worth the cost for this project.
A patio that will need to hold up to vehicular use should have the edging reinforced with rebar.