Foundation Cost per Metre

Search results for “foundation cost per metre” often mix three different metres: wall-run rates for strip/trench-fill, area rates for rafts, and pile-length rates for bored or driven piles. Comparing those numbers as if they were the same unit inflates or understates a budget before drawings exist.

This guide keeps the units separate, summarises published UK budgeting bands (not Mainline quotes), and explains the depth, width, reinforcement, spoil, access and ground factors that move a site figure. For interactive modelling use the groundworks cost calculator; for a whole-package overview start at /groundworks-costs. Frost founding depth belongs on the frost-depth guide — link it rather than re-deriving Building Regs here.

review Piling Contractors in Tonbridge and Concrete Foundations in Oxford.

When a budget range is useful — and when it is not

Use a per-metre foundation range at feasibility when you know (or can estimate) trench length, foundation type, and rough depth/width — for example a domestic extension strip, a small commercial trench-fill package, or a first-pass house perimeter budget. Do not treat a published £/m band as a tender figure when GI is missing, founding depth is unsettled, or the quote must include beam works, pile caps, or contaminated spoil.

Switch to area rates for rafts, and to dedicated piling cost pages when the engineer has moved off shallow foundations.

Cost drivers that move the figure

Founding depth and trench width change concrete and dig volume faster than “strip vs trench-fill” labels
Machine dig vs hand dig (or restricted access) can roughly double a linear-metre rate on the same geometry
Spoil classification, haul distance and tip fees often rival the concrete line on constrained urban plots
Reinforcement, sulphate notes and pump hire sit outside many brochure £/m figures
Clay, trees, water table or made ground push depth or force a change to raft/piles — changing the unit as well as the rate

Guide ranges help with budgeting. For a site-specific figure, send drawings and site details — or call for a quick scoping conversation.

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What you are usually paying for

A strip or trench-fill “per metre” package commonly bundles excavation to formation, concrete (and sometimes blinding), and basic backfill. Reinforcement, sulphate-resistant mix, temporary trench support, pumped concrete, Building Control attendance, below-DPC masonry, and licensed muck-away are frequently listed as extras or priced elsewhere.

Published UK guide bands for machine-dug domestic strip often sit around £95–£200 per linear metre depending on what is included and region; trench-fill guide bands often sit around £130–£240 per linear metre because concrete volume rises. Raft guide bands are typically quoted around £120–£260 per m² of footprint, not per metre run. Piling is a separate £/m of pile — see the piling cost-per-metre page. These are industry conversation ranges drawn from public UK cost guides; they are budgeting aids only and are not Mainline price lists.

Cost driver summary

Foundation type	Usual unit	Indicative published band	What often sits outside the band
Strip (machine dig, typical domestic geometry)	£ / linear metre of trench	Roughly £95–£200 / lin.m across public UK guides	Hand dig premium, reinforcement, pump, BC fees, below-DPC brickwork
Trench fill	£ / linear metre of trench	Roughly £130–£240 / lin.m across public UK guides	Extra concrete volume vs strip; still may exclude disposal class upgrades
Raft	£ / m² of footprint	Roughly £120–£260 / m² across public UK guides	Edge thickening, heavy reinforcement, services, dig under the slab
Piling	£ / linear metre of pile	See piling cost-per-metre page (type and depth dependent)	Working platform, testing, pile caps/beams, spoil from boreholes

Indicative UK published bands for budgeting only — not Mainline quotes. Confirm inclusions, VAT and site assumptions before using any figure.

Why published rates cannot replace a site quote

Published per-metre bands disagree because inclusions differ (dig only vs dig+concrete vs all-in domestic), VAT treatment varies by guide, and London/South East labour and logistics often add a regional premium. Depth driven by frost, heave or trees multiplies excavated volume and spoil; water and temporary support multiply plant hours. Once shallow trenches are no longer viable, the conversation leaves £/lin.m strip rates and moves to raft £/m² or piling £/m — different products, not a small uplift on the same rate.

How to get a usable figure

Send foundation drawings (or a clear sketch with lengths and assumed depths), GI summary if available, access photos, spoil assumptions, and whether you need strip, trench-fill, raft or piled construction. Use the calculator for order-of-magnitude modelling, then request a site-specific construction quote. Mainline prices construction from issued design information — we do not invent founding depths or substitute for structural design.

Information that improves quote accuracy

Foundation type confirmed (strip, trench-fill, pad, raft, or piled)
Total linear metres of trench/wall run — or raft footprint m² — stated
Design depth and width (or engineer’s schedule) attached
GI summary or known ground risks noted (clay, trees, water, made ground)
Access for excavator, concrete wagon or pump described
Spoil disposal assumption (reuse on site vs tip) written down
Whether reinforcement, blinding, pump and Building Control attendance are in scope

From budget conversation to priced package

Step 1: Lock the unit and foundation type
What this step delivers: Strip/trench-fill £/lin.m, raft £/m², or piling £/m of pile — not mixed.
Step 2: Quantify length, depth and width
What this step delivers: Trench run or footprint and design geometry understood from drawings or a clear sketch.
Step 3: List inclusions and exclusions
What this step delivers: Dig, concrete, steel, pump, spoil and inspections scoped the same way for every tenderer.
Step 4: Price from site information
What this step delivers: Guide bands used only for budgeting; commitment figure comes from a site-specific quote.

Project types where these drivers dominate

Domestic extension strip or trench-fill budgeting from wall-run length
Small new-build house perimeter where shallow foundations remain viable
Early contractor conversations before raft or piling is confirmed
Comparing published £/lin.m bands with a drawing-based quote package

Frequently asked questions

How much do strip foundations cost per metre in the UK?

Public UK cost guides commonly discuss machine-dug domestic strip foundations in a broad band of roughly £95–£200 per linear metre, with trench-fill often higher (around £130–£240 per linear metre) because more concrete is poured. Hand digging, deep trenches, poor access, reinforcement and spoil disposal can sit well above those bands. Treat the figures as budgeting aids only and obtain a quote from drawings.

Is foundation cost per metre the same as cost per m²?

No. Per metre (linear metre) usually means cost along the trench or wall run for strip or trench-fill foundations. Per m² usually means cost across the building footprint for a raft. Piling uses yet another metre — length of pile installed. Mixing the units is the most common budgeting error on this topic.

What information do you need for a foundation cost quote?

A usable quote normally needs foundation drawings or a dimensioned sketch, assumed or designed depths and widths, foundation type, GI notes if available, access constraints, and whether excavation and spoil disposal are included. Photos of access and neighbours help on tight plots. Without those, only a wide budgeting range is honest.

When should I budget raft or piling instead of a strip rate?

When ground investigation or the structural engineer shows that strip trenches would need excessive depth, temporary support, or still not achieve bearing — for example soft or variable ground, heave risk, or loads that need piles. At that point switch to raft £/m² or piling £/m pages rather than stretching a shallow strip rate.

Are online foundation cost-per-metre figures Mainline prices?

No. Bands on this page summarise published UK contractor and estimator guides for budgeting conversations. Mainline provides site-specific construction pricing from issued design information and a clear scope — not a national rate card.

Next steps from budget range to quote

Use these links to refine scope, then request a programme-ready quote:

We provide these services across the UK, including

London Richmond Chiswick Wimbledon Kingston Fulham Hammersmith Ealing

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Contact us for a no-obligation quote or to discuss your project. We'll advise on the best approach and provide clear pricing.

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Have foundation drawings or a trench-length sketch? Send them for a site-specific construction quote.

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