Cambridge Patios
Edging that stays in line and walls that hold their ground, built on a compacted base that lasts.
Why Edging Fails
Most edging failures come back to the same root causes, here is what a proper build addresses.
Edging set on less than 100 mm of compacted granular base shifts with every wet or frosty season.
The installer excavates to a minimum 100 mm, compacts fresh granular material, and resets the edging on a firm footing.
Water trapped in retained soil builds pressure against the wall face and pushes it forward over time.
Retaining walls are backfilled with granular material and fitted with a drainage outlet to relieve water pressure.
Edging blocks without haunching mortar or landscape adhesive drift outward as the ground moves beneath them.
Blocks are reset with landscape adhesive and haunching mortar so the edging course is locked against lateral movement.
Cambridge clay expands and contracts with moisture, undermining any edging that sits on undisturbed or uncompacted ground.
Where clay is present, the base material is replaced with compacted granular sub-base that does not move with moisture.
Scope of Work
From a single drifting edge course to a full retaining wall on a sloping garden, the work is scoped to the structural cause.
Lifting, compacting and resetting drifted or sunken edging blocks with haunching mortar and landscape adhesive.
Building a retaining wall on a compacted base with gravel backfill, drainage outlet and capstones.
Installing a clean, level edging course to finish the perimeter of a new or existing patio.
Holding back soil on a sloped site with retaining wall blocks sized to the height and load required.
Spiked restraints pinned into the sub-base to hold edging in line.
Coping stones that shed water away from the retained face.
Assessment of existing base before any edging is repositioned.
Checking falls and outlets before backfilling a retaining wall.
Why Choose Us
We schedule a survey that covers Cambridge ground conditions and quotes the structural work transparently.
The site visit assesses base depth, drainage and ground conditions before quoting.
Excavation, base material, drainage and edging are quoted as separate lines with no hidden groundwork costs.
Every survey accounts for local clay soil behaviour and frost heave risk, and specifies the base accordingly.
We schedule a full site survey and a written quote, not a quick handyman estimate.
Every retaining wall job includes a drainage assessment so water pressure is managed from the outset.
Pricing Estimates
| Job | Typical cost | Typical scope |
|---|---|---|
| Simple edging | £150-£500 | Short run |
| Patio edging | £500-£1,500 | Typical garden job |
| Small retaining wall | £1,200-£4,000 | Short wall section |
Common Questions
Loose edging almost always comes back to an inadequate base or mortar bed beneath it. If the sub-base was too shallow, poorly compacted, or mixed incorrectly, the edging shifts with ground movement and traffic. Clay-heavy ground makes this worse, as it swells and shrinks with moisture changes. Fixing the surface alone without addressing the base means it will fail again.
Patio edging holds the perimeter of a level or gently sloping surface in place. A retaining wall is needed when there is a significant height difference between two levels and soil pressure would push through standard edging. If your patio sits noticeably lower or higher than the surrounding ground, a retaining wall is the right solution.
Slabs that rock, edges that have sunk or tilted, gaps opening between the patio and the edging, and water pooling where it did not before are all signs of ground movement. Cracks running across mortar joints rather than along them also point to subsidence rather than surface wear. A survey will confirm whether the sub-base has shifted.
A correctly built retaining wall holds back soil pressure and prevents the ground behind it from pushing into or under the patio. It will not fix movement caused by a failed sub-base on its own. Both issues need to be addressed together, the wall manages lateral pressure, while a properly compacted base manages vertical settlement.
Often yes, if the slabs themselves are sound and only the perimeter has failed. The edging course is lifted, the base beneath it is re-compacted or rebuilt, and the edging is re-laid and mortared. If the failure has caused adjacent slabs to drop or crack, those sections will need lifting too. A survey confirms the extent before work starts.
Resetting a single loose edging stone is within reach of a careful DIYer. Anything involving a failed base, retaining wall, drainage, or repeated movement needs proper groundwork skills and the right compaction equipment. Getting the base wrong a second time means the same failure returns, often faster than the first time.
The most common cause is fixing only the edging without rebuilding the sub-base beneath it. Freeze-thaw cycles, clay ground swelling in wet weather, and poor drainage washing out the bedding layer all cause repeat movement. Edging fixed on a weak or uneven base will shift again within one or two winters.
As a general guide, a height difference of more than around 300mm between the patio surface and the surrounding ground usually calls for a retaining wall rather than edging alone. On steeper slopes, soil pressure is too great for standard edging to hold. The survey can assess the drop and soil type and advise the right approach.
Describe the garden, what is down there now and how it drains. We will schedule a survey and quote the work properly.