Edging Units and Concrete for a Driveway or Path (UK)
Edging units sit on a bed of concrete and are held by a wedge of concrete behind (the haunching). 10 m of edging takes 11 units of 1 m with 5% extra, and with a 100 mm bed and a 100 × 100 mm haunch 0.32 m³ of concrete, which is 4 bags of cement, 0.22 tonnes of sharp sand and 0.42 tonnes of gravel in a 1 : 2 : 4 mix. The edging calculator does it for your length.
Materials by length
With 1 m units, a 100 mm bed, 100 × 100 mm haunching and 5% extra:
| Length | Units | Concrete | Cement bags | Sharp sand | Gravel |
|---|---|---|---|---|---|
| 5 m | 6 | 0.16 m³ | 2 | 0.11 t | 0.21 t |
| 10 m | 11 | 0.32 m³ | 4 | 0.22 t | 0.42 t |
| 20 m | 21 | 0.63 m³ | 8 | 0.44 t | 0.83 t |
| 30 m | 32 | 0.95 m³ | 12 | 0.67 t | 1.25 t |
| 50 m | 53 | 1.58 m³ | 20 | 1.11 t | 2.08 t |
Bed and haunching size
The bed and haunch are where the concrete goes, so their size sets the volume. For 10 m:
| Size | Concrete | Cement bags |
|---|---|---|
| 100 mm bed, 100 × 100 mm haunch | 0.00 m³ | 1 |
| 150 mm bed, 100 × 100 mm haunch | 0.00 m³ | 1 |
| 150 mm bed, 150 × 150 mm haunch | 0.00 m³ | 1 |
A drive carries cars, so give it a deeper bed and wider haunching than a path. The edging maker's instructions rule, and the concrete calculator will size any other slab.
Mixing it yourself or ordering
A job of 0.32 m³ is a few hours with a mixer. Above about 0.5 m³ ready-mix is quicker, but loads have minimums. The mix should be fairly dry so it holds its shape as a wedge.
Laying edging
- Set a string line to the finished level, because the edging fixes the height of the paving beside it.
- Bed the units on the concrete, tap them level with a mallet, then haunch behind.
- Leave a few millimetres between units for the concrete to key in.
- Dry-lay a row first so that the last unit is not a sliver.
- Leave the concrete for a day or two before you load or compact against it.
See the paving calculator for the slabs. These are typical sizes: follow the instructions that come with your edging.
Frequently asked questions
How many edging units do I need?
Divide the length by the unit length and add 5%. 10 m of 1 m units takes 11.
How much concrete does edging need?
A 100 mm bed under the unit and a 100 × 100 mm haunch is 0.32 m³ for 10 m, with 5% extra.
What is haunching?
A wedge of concrete behind the units that holds them in place when the paving or drive is loaded.
How many bags of cement for 10 m of edging?
4 bags of 25 kg in a 1 : 2 : 4 mix, with 0.22 tonnes of sharp sand and 0.42 tonnes of gravel.
Do drives need more concrete?
Yes, a deeper bed and a wider haunch. Check the maker's instructions.
More guides
Tools & materials for this project
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Estimates only. Quantities depend on your materials, site and supplier. Confirm important numbers before you order, and check the Building Regulations and any planning rules for anything structural or close to a boundary.
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