What's Actually in a Contractor's Quote? A Private Clients Guide to Reading Between the Lines

Two contractors can quote for exactly the same extension and land 20% or more apart - and price isn't usually the reason. More often, one quote has quietly left things out. A vague description, a missing provisional sum, an “and associated works” catch-all covering who-knows-what: these are the details that turn an affordable-looking quote into a project that costs 15% more than you budgeted for, three months in.

If you're comparing contractor quotes for a New Build, Extension or Renovation, learning to read between the lines matters just as much as comparing the bottom-line figure. 

Here's what a proper quote should contain, the red flags worth spotting, and how to protect yourself before you sign anything.

The Anatomy of a Proper Quote

A genuine, reliable quote is really several documents in one, whether or not the contractor presents it that way. It should set out a clear scope of works describing exactly what's being built and to what standard; specification references — the actual make, model or grade of the materials being used, not just “kitchen supplied and fitted”; a schedule of what's included and, just as importantly, what's excluded; any provisional sums or prime cost (PC) sums for work that can't be priced precisely yet; a payment schedule tied to stages of work rather than arbitrary dates; and a realistic programme with a start date and duration.

If a quote is a single page with one number and a sentence of description, that's not really a quote - it's an estimate dressed up as one, and it leaves you exposed to almost unlimited “extras” once work is underway.

Red Flags to Watch For

A handful of patterns come up again and again in the quotes we review for private clients. None of them automatically means a contractor is being dishonest — but each one is worth querying before you sign.

• Vague lump sums — a single figure covering “all groundworks” or “all electrics” with no breakdown gives you nothing to benchmark against, and nothing to challenge later if it turns out to be wrong.

• Catch-all phrases — wording like “and associated works” or “as required” sounds harmless, but it's often where scope quietly expands, and cost with it, once the job starts.

• Missing provisional sums — costs that genuinely can't be fixed yet (drainage connections, existing structural conditions, unknown ground conditions) should be flagged with a stated allowance, not left out entirely.

• No specification detail — “supply and fit kitchen” tells you nothing about quality or cost, and leaves the contractor free to substitute a cheaper product mid-project while still meeting the letter of the quote.

• No exclusions list — if a quote doesn't tell you what's not included, assume everything unglamorous — skips, scaffolding, making good, decorating, landscaping — has been left out, and ask directly.

• Large upfront payment requests — a significant deposit before any work starts, with later payments not clearly tied to progress, shifts risk onto you rather than the contractor.

Provisional Sums and PC Sums, Explained

Two terms worth understanding properly, because they're where a lot of quotes go wrong. A provisional sum is an allowance for work that can't be accurately priced at quote stage — say, £3,000 for “unforeseen drainage works” — because nobody can know exactly what's needed until the ground is opened up. A prime cost (PC) sum works similarly for specific items, such as fittings or a kitchen, where an allowance is made pending your final selection.

Both are completely normal and, used properly, protect everyone. The problem is when they're set unrealistically low to make a quote look more competitive, then quietly “discovered” to be far higher once you've already committed to the contractor. A Quantity Surveyor benchmarks these allowances against what similar work actually costs, so you're not relying on the contractor's own estimate of the very costs they'll go on to charge you.

The Scope Gaps Homeowners Miss

Even in an otherwise solid quote, certain items tend to fall through the cracks simply because they sit at the edges of the main build: external works and landscaping reinstatement, drainage and utility connections, temporary services during the build, skip hire and waste removal, scaffolding, making good to adjoining areas, final decoration, and snagging once the main contractor has moved on.

None of these are exotic — they're standard parts of most projects — but they're exactly the sort of thing that gets assumed rather than written down. The fix is simple in principle: ask for every one of these to be explicitly addressed as included, excluded, or provisional, rather than left to assumption either way.

Before You Sign

Before agreeing to any quote, it's worth running through a short checklist:

• Does the scope match your drawings and specification exactly?

• Is every provisional and PC sum listed, with a stated allowance?

• Are exclusions listed explicitly, not just implied?

• Are payments tied to verified progress, not calendar dates?

• Is the programme realistic, with a genuine start and completion date?

How a Quantity Surveyor Helps

This is exactly the comparison work a Quantity Surveyor does as standard — reviewing quotes line by line, querying vague pricing, checking provisional sums against realistic costs, and making sure nothing's been quietly left out before you commit.