Quick Answer
UK groundworks are priced from three components: machine excavation at £85–£125 per m³, C25 ready-mix concrete at £110–£139 per m³ (ex VAT, plus about 7% ordering waste), and muck-away at £310–£360 per 6-wheel grab load — with dug soil bulking up around 30% before it is carted off. A typical 10 m × 0.6 m × 1 m trench-fill foundation works out at roughly £1,420–£1,870 excluding VAT.
The 2026 UK Rates This Calculator Uses
Every figure in this groundworks cost calculator comes from a published UK price guide — no invented rates. The estimate is a low–high range because that is how the guides themselves quote; your soil, access and postcode decide where you land in it.
| Component | 2026 guide rate (ex VAT) | Notes |
|---|---|---|
| Machine excavation | £85 – £125 per m³ | hand dig runs £85 – £145 per m³ |
| Ready-mix concrete (C25) | £110 – £139 per m³ | + delivery £50 – £200; London 15–25% higher |
| Muck-away, 6-wheel grab | £310 – £360 per load | 12–14 tonnes ≈ 8–9 m³ of bulked soil |
| Muck-away, 8-wheel grab | £370 – £420 per load | 16–18 tonnes, for bigger digs |
| Groundworker labour | £180 – £320 per day | up to £440/day in London |
| Line pump hire | £275 – £450 per day | where the truck can’t reach the trench |
How the Estimate Is Built
Groundworkers price a trench from its volume, and so does this tool. Concrete gets a 7% ordering allowance, and dug soil bulks up about 30% the moment it leaves the ground — which is why a “small” dig fills more grab lorries than you expect.
Dig cost = volume × £85–£125. Concrete = length × width × concrete depth × 1.07 waste × £110–£139.
Muck-away = volume × 1.3 bulking ÷ 8.5 m³ per 6-wheeler, rounded up to whole loads × £310–£360.
The concrete depth follows the foundation type: trench fill is poured to about 150 mm below ground level (fast, concrete-hungry), a strip footing takes roughly 300 mm of concrete in the trench bottom with masonry built up to damp-proof course on top (the bricklaying is not in this estimate), and dig only suits service or drainage trenches with no concrete at all.
Foundation Cost per Metre: How the Guide Bands Compare
Cost guides quote foundations per linear metre, but their bands disagree because each one bundles different things. For a standard 0.6 m wide, 1.0 m deep trench, this calculator’s component math lands at about £140–£185 per metre for trench fill and £100–£135 per metre for strip (dig + concrete + muck-away, ex VAT) — inside the published bands:
| Guide | Strip foundations | Trench fill |
|---|---|---|
| Checkatrade (machine dig) | £95 – £115 /m | £130 – £160 /m |
| Checkatrade (hand dig) | £170 – £220 /m | £220 – £280 /m |
| 2 Brothers (domestic, all-in) | £130 – £200 /m | £160 – £240 /m |
| This calculator (components) | ≈ £100 – £135 /m | ≈ £140 – £185 /m |
How to Use the Groundworks Cost Calculator
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Pick Foundation trench or Area dig
Use Foundation trench for footings and drainage runs, or Area dig for stripping ground under a slab, driveway or patio.
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Trench mode: enter the run and pick a type
Add up every side of the trench for the length (a 4 m × 3 m extension dug on three sides is 10 m), keep the standard 0.6 m width and 1.0 m depth unless you know better, then choose trench fill, strip or dig only. Use the picker beside each field to type in metres, centimetres, millimetres, feet or inches — 600 mm and 0.6 m give the same answer.
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Area mode: enter the footprint and depth
Type the area in square metres, square feet or square yards, and how deep the ground gets stripped — driveways and patios usually come off at 0.2–0.3 m (200–300 mm). If you only have lengths, the square metre calculator turns them into m², ft² or yd² first.
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Choose ex or inc VAT
Guide rates are quoted excluding VAT. If you are a homeowner paying a VAT-registered contractor, switch to “Including 20% VAT” to see the real bill.
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Read the range and the working
The result card shows the total low–high range, the split between dig, concrete and muck-away, and every calculation line — so you can sanity-check any quote against it.
Groundworks Cost Examples
Every row is reproducible in the calculator above (machine dig, ex VAT unless stated):
| Job | Dig volume | Concrete | Grab loads | Estimated range |
|---|---|---|---|---|
| Extension trench fill, 10 × 0.6 × 1.0 m | 6 m³ | 5.5 m³ | 1 | £1,420 – £1,869 |
| Same job, including 20% VAT | 6 m³ | 5.5 m³ | 1 | £1,704 – £2,242 |
| House strip footings, 80 × 0.6 × 1.0 m | 48 m³ | 15.4 m³ | 8 | £8,255 – £11,022 |
| Drainage trench (dig only), 15 × 0.45 × 0.6 m | 4.1 m³ | — | 1 | £654 – £866 |
| Garage base area dig, 30 m² × 0.3 m | 9 m³ | — | 2 | £1,385 – £1,845 |
For scale: a published full-service worked example for an 80-metre strip-foundation dig on a 4-bed house — including labour, pump hire and building control — lands at £17,500–£21,000. The gap between that and the £8,255–£11,022 component estimate above is the labour beyond the dig, the masonry, the pump and the fees: exactly the extras listed below.
