The thickness of the attachment
Setting edging in concrete and mortar
A fixed edge that keeps the paving in place
Kerbs edge and hold a paving or a bed in place. If the kerb is not secure, it shifts and the paving slides. This guide shows how to dig a trench, set kerbs plumb and in line in bedding mortar with haunching, and let the mortar cure before the paving loads the kerb.
Set out line and levels
Stretch a line along the alignment and level the edge is to follow — both in plan and in height. The top of the edging determines the level and fall of the paving, so the line is set out with the desired longitudinal fall built in.
Dig out the trench
Dig a trench along the line with room for the kerb, the mortar bed underneath and the haunching behind. The bottom is compacted so the mortar bed sits on a firm, load-bearing base and not on loose soil.
Mix the bedding mortar
Mix an earth-moist bedding mortar (cement and sand — CA mortar) according to the supplier's mixing ratio. The mortar must be dry enough for the kerb to stand in it without sinking, but moist enough to bond.
Lay the mortar bed and set the kerb
Lay a mortar bed in the bottom of the trench and set the kerb into it. Tap the stone gently into place with a rubber mallet until the top edge is flush with the string line in both height and alignment.
Align plumb and to the line
Check each kerb for plumb with a spirit level and for line against the string line (NfA 1992). Adjust while the mortar is still soft. A single crooked stone breaks the straight line, which the eye catches immediately.
Check both the front edge against the string line AND plumb — a stone can be flush at the top and still lean.
Back the kerb
Place a backing of mortar/concrete behind the kerb, so it cannot tip over or be pushed backwards when the paving is compacted up against it. The backing is what gives the edge its real strength.
Let the mortar cure before loading
Let the bedding mortar cure sufficiently before you lay and vibrate the paving up against the edge. If you load a fresh edge, it gets pushed out — and the kerb setting is lost. Follow the mortar manufacturer's curing time.
Plan kerb setting as the first task of the day, so the mortar can cure while you carry on working elsewhere.
Source
Based on Normer for anlægsgartnerarbejde 1992 (kerbs set in mortar, plumb and in line) and bedding mortar practice (supplier data); foundation dimensions are designed according to the project.