Drainage, culverts, fencing, gates and external works
Side drains, culverts, blockwork boundary walls, gates and gate houses, paving and kerbs — the external works that decide how a compound performs after the rains.
What this covers
External works are what a compound is judged by after the first rainy season. They are also the part of a project most often left to whoever is cheapest, and then repaired twice.
- Side drains and channel drains, including falls and outfalls that actually discharge somewhere
- Culverts, headwalls and crossings for vehicle access
- Perimeter fencing: blockwork walls, reinforced columns, barbed wire and security topping
- Gates and gate houses, including the concrete works and plinths that carry them
- Stone paving, kerbs, walkways and hard standing
- Compound levelling, filling and erosion control on sloping ground
- Borehole aprons, soakaways, septic and soakaway pit construction
Drainage is a design decision, not a trench
Water finds the lowest point, and if the lowest point is your neighbour's wall or your own foundation, the drain has failed regardless of how well the blocks were laid. Before we build a drain we establish where the water goes: the fall along the channel, the outlet, and what happens when the channel is full. On sloping ground we look at erosion upstream as well as on the site itself.
This is the work shown in the site footage further down this page: blockwork boundary wall and kerbing following a sloping boundary, with the drainage edge formed as part of the same job.
Fencing that stays standing
Set out and level
Fence line set out to the survey, with the top of wall following a consistent level or a designed step — not whatever the ground happens to do.
Found and column
Pad foundations at intervals, reinforced columns cast, and movement joints where the line is long. A wall without columns cracks.
Blockwork and topping
Blockwork in courses to line, with the chosen security topping fixed properly, not wired on and hoped for.
Finish and drainage
Plaster or fair-face finish as specified, coping or cap to shed water, and the drainage or kerb at the base to stop water undermining it.
What changes the price
| Factor | Effect |
|---|---|
| Length, height and thickness of wall | The obvious drivers: block count, columns and concrete volume all scale with length and height. |
| Ground slope | Stepped walls need more columns and more concrete than a level run, and the ground may need benching. |
| Ground conditions | Rock or soft fill changes excavation and foundation cost sharply. |
| Security specification | Barbed wire, electric fencing, spikes or a rendered and painted wall each move the number. |
| Access for materials | A boundary that cannot be reached by lorry means head-loading sand, blocks and water. |
| Drainage integration | Forming the drain or kerb with the wall is cheaper than coming back later. |
Fencing, drainage or a full compound?
Send the boundary length, a site photograph and what the drain has to cope with. We will price it and tell you where the ground will cost you.
Replies are sent by WhatsApp. Every message to info@peterch.org is read — include a working number and we will come back to you the same working day.