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
Spoil is bulkier out of the ground than it was in it, so the heap is always bigger than the hole it came from. It leaves by the lorry and is priced by the load, dearer for wet clay than for sand, dearer again for anything contaminated. What you want on the page is the number of loads allowed for and the rate for one more. Where that line is missing, the lorries still come. You simply meet the figure later, on an invoice.
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, not a specification. You want a figure in millimetres, the stone named, and a line saying it goes in as layers with a compactor over each one. Depth is the cheapest thing in the whole job to shave, because nobody can measure it through a finished surface. A contractor who writes the number down has closed off his own way out.
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 is the opposite. A contractor is 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 and weighbridge tickets for what left, and priced at rates stated in the quote, not invented on the day.
Find the VAT before you compare anything
The largest honest reason two prices for the same job land a long way apart isn’t in the ground at all. It’s tax. VAT at the standard rate adds a fifth to the bill, and it is the easiest thing on a quote to read straight past, because it tends to sit in small type under the total, when it is there at all. Three things are worth settling on every quote you are handed.
- Is the firm VAT-registered? Registration becomes compulsory once taxable turnover passes the threshold HMRC sets, £90,000 across any rolling twelve months as things stand, though it is worth checking the current figure. Below it, registration is voluntary. So a smaller outfit may genuinely charge no VAT, and that is lawful and ordinary rather than a dodge. If VAT is being charged, there is a VAT number behind it, and it belongs on the quote and on every invoice after.
- Does the figure include VAT, or sit before it? “Including VAT” and “plus VAT” are a fifth of your whole job apart. If the paperwork doesn’t say plainly which it is, ask, and have the answer written on the quote rather than agreed over the phone.
- Which rate applies to your work? Twenty per cent is standard, but building work does not all sit there. Work in the course of constructing a new dwelling can be zero-rated; some conversions, and homes that have stood empty for years, can fall to five per cent; an extension to a house you already live in is normally charged at the standard rate. The rules run to a whole HMRC notice and turn on details of your particular project, so let your accountant or the contractor’s confirm the rate in writing before anything is signed.
Then put both quotes on the same footing before you judge either. Reading an inc-VAT price against an ex-VAT price is not comparing two contractors. It is comparing two different questions, and the figure that looks cheaper on the page can easily be the dearer job. Add the tax on where it is missing, take it off where it isn’t, and look again. A gap that seemed alarming sometimes closes to almost nothing once both figures are quoted the same way. And if it doesn’t, at least what’s left is a real difference in the work.
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, rather than 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.
- No word on VAT anywhere. Neither a rate, nor a registration number, nor the words “inclusive” or “plus”. That silence can move the real figure by a fifth.
- 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.
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