The short answer
Foundations are usually priced per linear metre of trench. A basic strip foundation typically runs around £130–£200 per linear metre for standard domestic depths, while a groundworker may charge roughly £120–£150 per metre for a trench around a metre deep and 0.6m wide. Across a whole house that often works out at roughly £10,000–£18,000 for a three-bedroom property, depending on the perimeter and ground. The type you need is set by the ground: strip and trench-fill suit firm soil, a raft spreads load on weaker ground, and piled foundations reach down to stable strata on poor or made ground — each step up adding cost.
Foundations are the part of groundworks where ground conditions matter most. The type is rarely a free choice — it follows what the soil can carry. Here is how the main types compare and what they cost.
At a glance
- Strip foundation~£130–£200 / linear metre
- Basic trench (1m deep)~£120–£150 / metre
- Three-bed house~£10,000–£18,000
- Raftfor weaker, even ground
- Piledfor poor or made ground
How the foundation types compare
Strip foundations — a concrete strip under the load-bearing walls — are the common, lower-cost choice on firm ground. Trench-fill fills the trench almost to the top with concrete, saving bricklaying time but using more concrete, so it trades labour for materials. A raft is a single slab that spreads the load across the whole footprint, used where the ground is weaker or uneven. Piled foundations drive or bore down to firmer strata and are needed on poor, made or shrinkable ground — they are the most involved and the most expensive. Your contractor or engineer chooses the type from the ground investigation, not from price alone.
| Type | Best for | Relative cost |
|---|---|---|
| Strip | firm ground, standard loads | lower |
| Trench-fill | firm ground, faster build | mid (more concrete) |
| Raft | weaker or uneven ground | higher |
| Piled | poor / made / shrinkable ground | highest |
General comparison for guidance — the type is set by the ground investigation. Sources: MyJobQuote and trade cost data.
Why depth and ground change the cost
The deeper the trench and the more concrete it takes, the more you pay — and depth is often dictated by factors like nearby trees, clay shrinkage or services. Poor soil, a high water table or made ground can mean stepping up from a strip to a raft or piles, which raises the cost substantially. This is why foundations are quoted after a look at the ground, and why a building-control or engineer's input on depth is part of getting the number right.
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Frequently asked questions
How much do foundations cost per metre in the UK?
Strip foundations typically run around £130–£200 per linear metre for standard domestic depths, and a basic metre-deep trench is often roughly £120–£150 per metre. Across a three-bedroom house that usually works out at around £10,000–£18,000 depending on perimeter and ground.
Which foundation type is the lowest-priced?
Strip foundations are usually the lowest-priced choice on firm ground. Trench-fill, raft and piled foundations cost more, but the type is set by the ground conditions rather than chosen on price — weaker or made ground needs a stronger, more expensive foundation.
Why do foundation costs vary so much?
Because depth and ground decide them. Trench depth, soil type, water table, nearby trees and the foundation type all move the figure, so the accurate cost comes from a contractor or engineer who has assessed your ground.
Sources & further reading
Figures on this page are typical UK ranges drawn from published sources and depend on your specific site. They are guidance, not a quotation.