Groundworks Costs in Swansea
Groundworks costs in Swansea in 2026 are broadly in line with South Wales averages, with some variation by area based on ground conditions.
| Job | Swansea typical cost |
|---|---|
| Strip foundations (per m run) | £80–185 |
| Concrete slab (per sq m) | £95–195 |
| Drainage installation (per m run) | £42–125 |
| Soakaway installation | £620–1,900 |
| Retaining wall (per m) | £190–480 |
Swansea Ground Conditions
Swansea's varied geology affects foundation design and cost:
City centre and SA1 (Swansea Bay): Made ground over soft alluvial deposits. Extension and basement projects may require deeper foundations or piling, always commission a ground investigation for SA1 area projects.
Uplands (Morriston, Llansamlet): Generally better ground, former colliery areas may have variable fill. Check historical mining maps before foundation design.
Gower peninsula: Rock close to surface in many areas, slower and more expensive excavation but generally excellent bearing capacity.
West Swansea (Sketty, Derwen Fawr): Mixed ground, often former agricultural land with reasonable bearing capacity.
A structural engineer can advise on appropriate foundation solutions for your Swansea location before groundworks are tendered.