The short answer
Beam-and-base underpinning typically costs around £1,800–£3,000 per metre of wall in the UK, sitting between traditional mass concrete and full mini-piling on price. Instead of supporting the whole wall on continuous concrete, it casts reinforced concrete bases (pads) at firm bearing points and spans reinforced concrete beams between them, so the wall's load bridges over weaker ground rather than bearing on it everywhere. It is chosen where the ground is variable — some firm spots, some weak — and where continuous mass concrete would be uneconomic or unreliable, but full piling is not yet warranted. The per-metre rate reflects the reinforcement and design it needs: a structural engineer specifies the beam sizes, base positions and steel, and the work is inspected by Building Control. As with all methods, depth, access, soil and region move the figure within the band.
Beam-and-base is the middle option an engineer reaches for when ground is patchy. It uses steel-reinforced concrete to bridge weak zones. The figures below are typical UK ranges for guidance, not quotations.
Typical UK costs
- Beam-and-base per metre~£1,800–£3,000
- Position on pricebetween mass concrete and piling
- Methodreinforced beams span between bases
- Best forvariable / patchy ground
- Designengineer-specified steel and bases
How beam-and-base works
- Bases at firm points: reinforced concrete pads are cast where the ground is competent.
- Beams bridge the gaps: reinforced concrete beams span between those bases, carrying the wall over the weaker zones between them.
- Load transfer: the wall's weight is concentrated onto the firm bearing points rather than spread evenly, which is why it suits variable ground.
- Engineered: beam depths, base sizes and reinforcement are all designed by a structural engineer for the specific loads and soil.
| Method | Per metre | Ground suited to |
|---|---|---|
| Mass concrete | £1,500–£2,500 | uniformly stable, modest depth |
| Beam-and-base | £1,800–£3,000 | variable / patchy ground |
| Mini-pile | £2,000–£4,000 | weak near-surface, deep strata |
Indicative UK guidance. Sources: Checkatrade underpinning cost guide and structural engineering practice.
When an engineer chooses it
A structural engineer specifies beam-and-base when a soil investigation shows the bearing ground is inconsistent — firm in places, weak in others — so that continuous mass concrete would either be unreliable over the soft zones or uneconomically deep. It can also pair with piling, where the beams span between pile caps rather than shallow bases, in genuinely poor ground. The reinforcement and design push the per-metre rate above plain mass concrete, but it can be more economical than piling the entire length where only parts of the ground are weak. Because the load paths matter, this is firmly an engineer-designed method, not something to specify by rule of thumb, and Building Control inspect the reinforcement before concrete is poured.
What drives the rate
Beam-and-base costs more per metre than plain mass concrete chiefly because of the steel reinforcement and the engineering it requires. The beams have to be sized to span the gaps between bases and carry the wall loads, which means a structural engineer's calculations, reinforcement detailing and inspection of the steel before concrete is poured. Within the £1,800–£3,000 band, the rate rises with the span between firm bearing points (longer spans need deeper, more heavily reinforced beams), the depth to competent ground for the bases, and access — hand-dug, confined sites cost more than machine-accessible ones. Where the bases themselves have to go very deep, the method shades into piling, with beams spanning between pile caps instead of shallow pads. As always, the fixed costs of engineer, Building Control, any party wall surveyors and making good sit on top of the per-metre structural figure.
| Factor | Effect on rate |
|---|---|
| Span between bases | longer = deeper, heavier beams |
| Depth to firm bearing | deeper bases = higher cost |
| Reinforcement design | steel + detailing add cost |
| Access | hand-dig / confined = higher |
General UK guidance. Source: Checkatrade underpinning cost guide and engineering practice.
How it fits the wider repair
Beam-and-base is rarely a standalone decision; it is one option a structural engineer weighs after a soil investigation reveals how the ground behaves along the affected wall. If the investigation shows reasonably uniform stable soil, mass concrete is more economical; if it shows weak ground throughout or very deep competent strata, piling is more appropriate; beam-and-base earns its place in the middle ground of variable conditions. Because it is engineer-designed, the work is notifiable to Building Control, who inspect the reinforcement and the bases, and where it sits near a boundary the Party Wall etc. Act 1996 applies. As with all underpinning, the durable repair also depends on dealing with the original cause of movement — a leaking drain or a tree — so that the new foundation is not undermined by the same problem that triggered the work.
For homeowners, the practical takeaway is that beam-and-base is a sign the engineer has read the ground carefully rather than reaching for a one-size answer. It is specified precisely because a soil investigation has shown the bearing capacity varies along the wall, and the design concentrates the load onto the firm spots while bridging the soft ones. That tailoring is why the per-metre rate sits above plain mass concrete: you are paying for reinforcement and calculation, not just concrete and digging. When comparing it against the alternatives, the question is not which method is lowest-cost in the abstract but which the soil report supports — mass concrete where the ground is uniformly sound, beam-and-base where it is patchy, piling where it is weak throughout or very deep. A quote that names beam-and-base should come with the engineer's reasoning from the soil data, so you can see the method was chosen to fit your ground rather than picked at random.
Because beam-and-base is engineer-designed rather than a standard dig, the quote should read differently from a plain mass-concrete one, and knowing what to look for helps you judge whether you are being charged fairly. The price reflects reinforced concrete bases at calculated centres with a ground beam spanning between them, so the metre rate sits above mass concrete to cover the steel, the design and the more involved excavation. What you want to see behind that rate is the engineer's reasoning from the soil investigation: which spots carry the load, why the beam spans where it does, and why this method was chosen over mass concrete or piling for your particular ground. A beam-and-base scheme proposed without that underlying soil data is a flag, because the whole point of the method is that it is tailored to variable bearing capacity along the wall. Where the ground genuinely is patchy — firm in places, soft in others — beam-and-base is often the most economical correct answer, bridging the weak spots without the expense of piling the entire length. So the figure is best assessed not against a generic metre rate but against the engineer's justification for using this method here, which is what confirms the cost is buying the right solution for your soil.
Frequently asked questions
What is beam-and-base underpinning?
A method where reinforced concrete bases are cast at firm bearing points and reinforced concrete beams span between them, so the wall's load bridges over weaker ground. It suits variable ground where continuous mass concrete would be unreliable.
Is beam-and-base more expensive than mass concrete?
Usually, at around £1,800–£3,000 per metre against £1,500–£2,500 for mass concrete, because of the steel reinforcement and fuller engineering design. It can be cheaper than piling the whole length where only parts of the ground are weak.
When is beam-and-base used instead of piling?
When the ground is patchy rather than uniformly poor, so firm bearing points exist for the bases. Where near-surface ground is weak throughout or stable soil is very deep, a structural engineer is more likely to specify mini-piling.
Sources & further reading
- Checkatrade — underpinning cost guide
- RICS — subsidence and foundations guidance
- Planning Portal — Building Regulations: structure
Figures on this page are typical UK ranges drawn from published sources and depend on your specific property. They are guidance, not a quotation.