Structural retaining walls to hold back sloped or raised ground
Retaining Walls
A retaining wall is a structural wall built to hold back soil or a change in ground level, most often to create a level garden area, terrace a slope, or prevent erosion near a boundary or driveway.
Definition
What Retaining Walls covers
Retaining walls resist the lateral pressure of retained soil behind them, and their design — foundation depth, wall thickness, drainage and reinforcement — depends on the height retained, the ground conditions and the material used, which may be masonry block, brick, poured concrete, timber sleeper or gabion. Taller retaining walls, or those near a boundary or supporting a driveway, typically need proper structural design rather than a standard garden wall build-up.
Suitable for
- Sloped gardens being terraced into level areas
- Raised beds or planters that need a structural retaining edge
- Driveways or patios cut into a slope
- Boundaries where a level change needs to be held back safely
Not suitable for
- Very low edging (under a few hundred millimetres) retaining planting beds, which doesn't need full structural design
- Sites with unstable or contaminated ground requiring specialist geotechnical investigation first
Process
How the work is carried out
- 01
Site survey
Assessing the height and length of ground to be retained, soil type, drainage and access for machinery.
- 02
Design
Sizing the wall, foundation and any reinforcement for the height and loading involved — engineer-designed for taller or loaded walls.
- 03
Foundations and drainage
Excavating and casting a suitable foundation, and installing land drainage and weep holes behind the wall.
- 04
Wall construction and backfill
Building the wall in the agreed material, then backfilling in stages with appropriate drainage material.
Typical timescale
A typical garden retaining wall takes from a few days to a couple of weeks on site depending on height, length and material, with longer runs or engineer-designed walls taking longer. Confirmed in your quotation after survey.
Cost guidance
Retaining walls typically cost £150–£350 per m² in our area, with the wall's height, the ground conditions and the material — block, brick, timber sleeper or gabion — being the main factors that move the price within that range. We provide an itemised quotation after a site visit rather than a fixed headline price.
Limitations and exclusions
- Structural calculations for taller or loaded retaining walls are provided by a qualified structural engineer where required
- Walls near a boundary may be subject to the Party Wall etc. Act 1996 or require neighbour agreement
- Ground conditions found on excavation (e.g. unexpected services or unstable soil) may require design changes and are priced as they arise
Areas we cover
Retaining Walls across Sussex, Surrey, Kent and South London
Local property styles, planning authorities and neighbourhood coverage for retaining walls in each town we work in.
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FAQs
Retaining Walls FAQs
Do I need planning permission for a retaining wall?
Most garden retaining walls fall under permitted development, but taller walls, those near a public highway, or in a conservation area, may need planning permission or Building Regulations consideration — we confirm the position for your specific site during survey.
Does a retaining wall need its own foundation and drainage?
Yes. A retaining wall needs a foundation sized for the height and loading involved, plus drainage behind the wall (such as land drain and weep holes) to relieve water pressure — without this, walls are prone to bulging or failing over time.
What's the best material for a retaining wall?
It depends on the height, budget and look you want: masonry block or brick suits most garden situations and matches existing brickwork, timber sleepers suit lower, more informal retaining, and gabion baskets work well on larger or more rustic level changes. We advise on the right option during survey.
Discuss your retaining walls project
Tell us about the property and what you have in mind, and we'll arrange a site visit.
Last reviewed 2026-07-28.