Two quotes for the same hole in the ground can be a long way apart. The difference is rarely the digging — it’s what each contractor has chosen to write down.
Two quotes land for the same job. One is a page and a half of line items with quantities against each. The other is a single tidy figure — usually the smaller one. Most people are drawn to the short quote and the small number, and that instinct is exactly backwards. Groundworks is buried the day it’s finished. The paperwork is the only place you will ever see the job in full, and a contractor who won’t describe the work in writing is asking you to buy something sight unseen.
What a proper quote itemises
You don’t need to price the lines yourself. You just need to check they exist. Six things should appear with quantities against them, not adjectives.
Excavation, in cubic metres
“Dig foundations as required” is not a quantity. A good quote states how much material is coming out — depth, width, volume. If the volume isn’t written down, neither is the price of removing it, and that argument arrives mid-dig, when the machine is on your lawn and your leverage is in the skip.
Muck-away
Soil takes up more room out of the ground than in it — as a rule of thumb, a quarter to a third more once it’s loosened. It leaves by the lorry-load and is charged by the load; more for clay, more again if it’s contaminated. Muck-away is often the line that surprises people, which is exactly why honest quotes state it and optimistic ones go quiet.
The foundation spec
Concrete grade, trench width, assumed depth — and the words “subject to building control approval”, because the inspector who looks into your open trench has the final say on depth, whatever anyone assumed at quote stage. Our foundations guide explains what those depths are responding to.
Drainage, run by run
Pipe diameter, the fall, where each run connects, how many inspection chambers. “Connect drainage” as a single line tells you nothing about whether anyone has thought about where the water actually goes.
Sub-base depths, in millimetres
“Hardcore base” is a phrase. “150mm compacted Type 1” is a specification. The stated depth is what stops a drive dipping at the gate two winters in — and it’s the easiest thing in the job to quietly thin out, because once it’s surfaced nobody can see it.
Reinstatement
Who puts the lawn back. Who makes good the verge, the fence line, the neighbour’s gravel where the lorries turned. If it isn’t written down, the answer is usually you.
A quote that itemises the boring parts was written by someone who intends to do them.
Provisional sums are a good sign
A provisional sum is a stated allowance for something that genuinely can’t be priced until the ground is open — what’s under the old drive, whether a soft spot needs digging out, where the existing drain actually runs. It looks like vagueness. It’s the opposite: a contractor telling you, in advance and in writing, where the uncertainty in your job lives and roughly what it might cost to resolve.
The quote with no provisional sums on ground nobody has opened isn’t more certain — it’s just quieter about the risk, and the risk hasn’t gone anywhere. What matters is how the sum becomes a real figure: agreed with you before the extra work is done, supported by evidence — photographs of what was found, weighbridge tickets for what left — and priced at rates stated in the quote, not invented on the day.
Questions for any contractor — including us
None of these are rude. A good contractor answers them comfortably, because they’re the questions they’d ask in your position.
ASK YOUR CONTRACTOR
- Can I see your public liability insurance certificate — not just be told it exists?
- Who will actually be on site each day, and who supervises them?
- If the ground surprises you, do you stop and price the change with me before spending my money?
- Are payments staged against work completed, or against dates?
- Is extra work agreed in writing before it happens, or itemised on the final invoice after?
The ground-conditions question matters most around here. In this corner of Buckinghamshire the ground can change within a single garden — clay over chalk, pockets of made ground where something stood before — so “what happens when we find something” is not a hypothetical. The answer you want is boring: stop, show you, price it, agree it in writing, carry on.
Red flags
- One round number for the whole job. Nobody prices excavation, concrete, drainage and disposal and lands on a figure ending in three zeros — unless they never priced the parts.
- No muck-away line at all. The spoil still exists. The cost still exists. Only the honesty is missing.
- “Allowances” with no quantity attached. Allowed for what, and how much of it?
- A price well below the others, with no explanation of what’s been left out. It’s rarely generosity.
- A large payment wanted before a machine arrives. A modest deposit for materials can be fair; front-loading the job is not.
- Foundations in the job, but no mention of building control or an engineer anywhere in the quote.
When the quotes are in, don’t compare bottom line against bottom line — compare line against line. Where one quote has a number and another has silence, the silence is the number you can’t see yet. Make the cheap quote account for what it’s left out, in writing, before anyone’s digger comes through your gate.
Planning something on your own plot?
Request a Quote