Groundworks Costs in Cardiff
Cardiff groundworks costs in 2026 are broadly in line with South Wales averages. The city's varied geology, alluvial deposits in Cardiff Bay and Leckwith, clay and made ground in many areas, harder rock on the northern fringes, affects foundation design and cost.
| Job | Cardiff typical cost |
|---|---|
| Strip foundations (per m run) | £85–190 |
| Concrete slab (per sq m) | £100–200 |
| Drainage installation (per m run) | £45–130 |
| Retaining wall (per m) | £200–500 |
| Soakaway installation | £650–2,000 |
| Site clearance (per sq m) | £8–25 |
Cardiff's terrace and semi-detached housing creates specific groundworks challenges, confined access, proximity to neighbouring foundations, and live services in congested urban conditions all add cost compared with rural sites.
Finding a Groundworks Contractor in Cardiff
Cardiff has several groundworks firms operating locally, ranging from small specialists to larger contractors capable of complex piled foundations and drainage systems. For extension and new build work, your architect or structural engineer can often recommend experienced local groundworks contractors.
For drainage work specifically, members of the British Drain and Pipework Association (BDPA) have additional professional accountability.