The Complete Guide to Builder Quotes in the UK

In short: Get at least three written quotes, not estimates. Make sure each one includes a full scope of works, itemised costs, payment schedule, and exclusions list. Compare them line by line - not just the bottom-line figure. Never pay more than 10–15% upfront. And if a builder won't put it in writing, walk away.

That's the summary. The rest of this guide walks you through the entire process - from getting your first quote to protecting yourself once the work starts.

Why builder quotes matter more than you think

A builder's quote isn't just a price tag. It's the document that defines what you're paying for, when you're paying, and what happens when things go wrong. Get a good quote and you've got a clear contract, a paper trail, and leverage if work doesn't meet expectations. Get a bad one - vague, incomplete, verbal - and you've got nothing but a number on a text message and a builder who remembers the conversation differently to you.

The average UK extension costs between £30,000 and £80,000. A loft conversion runs £40,000 to £65,000. Even a bathroom refurbishment can hit £10,000 to £15,000. These aren't small purchases. They deserve the same scrutiny you'd give to buying a car - probably more, since you can't return a half-built kitchen.

And yet, most homeowners spend more time comparing phone contracts than comparing builder quotes. Partly because construction quotes are confusing. Partly because builders don't make it easy. And partly because nobody teaches you how to do it.

This guide fixes that. It covers every stage of the process, links to detailed articles on each topic, and gives you a practical framework for making confident decisions about your project.

Step 1: Getting quotes - how many and from whom

Before you can compare anything, you need quotes on the table. The standard advice is to get at least three. We'd suggest aiming for three to five, and here's why: three gives you a low, middle, and high to compare. Five gives you a clearer picture of the market rate and helps you spot outliers in both directions.

The number matters less than the quality. Five identical one-page PDFs with a lump sum figure aren't useful. Three detailed, itemised quotes from builders who've actually visited your site and understood the job? That's gold.

How to get quotes that are actually comparable

The biggest mistake homeowners make is giving each builder a different brief. One gets a vague phone conversation. Another gets a detailed walkthrough. The third gets forwarded the architect's drawings. No wonder the quotes come back wildly different - they're pricing different jobs.

Give every builder the same written brief. Include:

• Drawings (architect plans, or at minimum clear sketches with dimensions)
• Materials specification (or state that you want the builder to recommend)
• What you're supplying (kitchen units, bathroom fittings, tiles, etc.)
• Access information (rear access only, shared driveway, conservation area, etc.)
• Your timeline (when you'd like to start and finish)

The more consistent your brief, the more meaningful the comparison.

Quote vs estimate - know the difference

This trips people up constantly. A quote is a fixed price for a defined scope of work. Once you accept it, the builder is legally bound to that figure. An estimate is a rough guide - not binding, can change, and often does.

The problem: many builders use the words interchangeably. You ask for a "quote" and receive a document titled "Estimate" - or the other way round. What matters isn't the title on the page. It's whether the document commits to a fixed price for a specified scope of work. If it says "approximately" or "in the region of," that's an estimate regardless of what it's called.

Our detailed guide on quotes vs estimates explains the legal position, what each document means, and how to make sure you're getting a binding commitment.

Fixed price vs day rate

Most domestic building work should be quoted as a fixed price. That gives you cost certainty - you know what you're paying before a single brick is laid.

Day rates have their place: small repair jobs, investigative work where you need a builder to open up a wall and see what's behind it, or ongoing maintenance. But for a defined project like an extension or a bathroom refurbishment, a fixed-price quote is almost always the better choice.

The typical day rate for a general builder in 2026 is £200–£280 across most of England, rising to £250–£350 in London and the South East. Our tradesperson day rates guide has the full breakdown by trade and region. If a builder suggests day rate for a large project, ask why they can't fix the price - and consider it a yellow flag if the answer isn't convincing.

Step 2: Understanding what's in the quote

You've got your quotes. Now you need to actually read them - all of them, properly. This is where most people fall down. They skip to the total, compare three numbers, and pick the cheapest. That's a recipe for problems.

What every quote should include

A proper builder's quote isn't a one-page letter with a price at the bottom. It should contain:

If any of these are missing, ask for them before you sign. Our full checklist on what a builder's quote should include goes through each item in detail, with examples of good and bad practice.

How to read a quote properly

Reading a builder's quote isn't just about checking the maths. It's about understanding what's there, what's missing, and what's deliberately vague.

Start with the scope. Read every line and check it against what you actually discussed. Phrases like "works as discussed" or "as per site visit" are red flags - they leave room for the builder to claim that something was never agreed.

Then check the exclusions. This is where the real cost differences hide. One quote might look £5,000 cheaper until you realise it excludes scaffolding, skip hire, building control fees, and making good to the existing surfaces. Add those back in and it might be the most expensive of the three.

Our guide on how to read a builder's quote walks through the five things to check first and the red flags to watch for at each stage.

Step 3: Comparing quotes properly

This is the step that separates homeowners who get good value from those who get burned. Comparing quotes isn't about finding the lowest number. It's about understanding what each number actually represents.

The line-by-line method

The only reliable way to compare builder quotes is to break them down and compare like with like. That means:

1. List every item from all three quotes in a single table
2. Mark inclusions and exclusions for each quote against each item
3. Normalise the scope - if one excludes scaffolding, add the scaffolding cost so you're comparing true totals
4. Compare materials - different specs mean different costs (and different quality)
5. Compare payment terms - a quote requiring 50% upfront is riskier than one with stage payments

Our complete method for comparing builder quotes provides a step-by-step framework and a downloadable comparison table.

Is the price actually fair?

Once you've normalised the quotes, you need to check whether the prices are reasonable. The most reliable benchmark is cost per square metre for your area and project type.

In 2026, a single-storey rear extension typically costs £1,800–£2,400/m² across most of England, rising to £2,200–£3,000/m² in London and the South East. Two-storey extensions run lower per square metre (£1,400–£1,800/m²) because foundations and roof costs are shared.

If a quote is more than 20–30% above the regional average with no clear explanation - difficult access, conservation area, premium specification - it's worth questioning. Our guide on checking whether your quote is too expensive provides detailed benchmarks by project type and region, plus the common reasons a quote might be legitimately higher.

When cheap is expensive

The cheapest quote should make you nervous, not relieved. A quote that's 15% or more below the others usually means one of three things: the builder has missed something, they've underpriced to win the job, or they're planning to make it up with extras once work starts.

The most common cause of a low quote is missing scope items. The builder hasn't included structural engineer fees, building regulations, or the cost of making good to existing surfaces. Once those appear as "extras" mid-build, the cheap quote isn't cheap any more.

Step 4: Spotting red flags

Not every builder is honest. Not every quote is genuine. And not every warning sign is obvious. Here's what to watch for.

Overcharging warning signs

There's a difference between a fair price for quality work and a builder who's inflating the numbers. The seven warning signs of overcharging include:

• A quote significantly above the regional average with no explanation
• A high labour-to-materials ratio (above 60% labour)
• Vague line items - "sundries," "contingency," "miscellaneous" - without detail
• Pressure to decide quickly or pay a large deposit
• Refusal to break down the price when asked

Some of these have innocent explanations. A high labour ratio might reflect a project that's genuinely labour-intensive. But if several red flags appear in the same quote, pay attention.

The written quote problem

If a builder won't give you a written quote, that's a serious red flag. A verbal quote gives you almost no legal protection. "He said he'd do it for twelve grand" is worthless in a dispute if the builder says he said fifteen.

Every reputable builder provides written quotes. It's standard practice. If someone resists, it usually means they want the flexibility to change the price later - and that flexibility comes entirely at your expense.

Deposit demands

A builder asking for 50% of the project cost as a deposit is not normal. The standard deposit for building work in the UK is 10–15% of the total. Anything above 25% is a red flag.

A large deposit shifts the financial risk from the builder to you. If they disappear with your money, or go bust mid-project, you're an unsecured creditor - which means you're at the back of the queue and unlikely to see your money again.

Reasonable payment structure for a typical extension:

Stage payments should always be tied to completed milestones, not calendar dates. If the builder hasn't finished the foundations, you don't pay the foundations payment - regardless of how many weeks have passed.

Step 5: Protecting yourself during the project

Getting a good quote is the foundation. But things can still go wrong once work starts.

Price changes after work begins

Your builder has started work, and now they say the price needs to go up. This is one of the most stressful moments in any building project. Whether it's legitimate depends on why.

Legitimate reasons for a price increase:

• Genuinely unforeseen problems (rotten joists behind plasterboard, contaminated ground, asbestos)
• Changes you've requested to the original scope
• Material price increases covered by a fluctuations clause in the contract

Not legitimate:

• The builder underquoted and now realises the job costs more than they expected
• They're adding items that should have been in the original quote
• They're inflating prices because they think you're committed and won't push back

Under the Consumer Rights Act 2015, the price in your contract stands unless both parties agree to a variation. Get any agreed changes in writing before the work is done.

Cash payment risks

If your builder asks you to pay in cash, think carefully. It's legal - there's no law against it. But cash leaves no paper trail. No bank record. No proof of payment. If a dispute arises, you've got nothing to show except your word.

And the elephant in the room: builders who insist on cash are often doing so to avoid declaring the income. That's tax evasion, and if HMRC comes knocking, being the person who facilitated it isn't a comfortable position.

Bank transfer. Always. It takes thirty seconds and creates an automatic record.

When the builder goes quiet

You've signed the contract. Paid the deposit. Cleared the house. And then... nothing. The builder hasn't started work. They keep saying "next week" and next week never comes.

A gap of 2–4 weeks between signing and starting is normal - builders finish one job before beginning the next. Beyond that, you need a firm start date in writing. If they won't give one, set a deadline (typically 14 days) and state in writing that you'll consider the contract cancelled if they don't start by then.

If you've paid a deposit and the builder never starts, you're entitled to a refund under the Consumer Rights Act 2015. Contact them in writing first. If that fails, contact Citizens Advice or your bank if you paid by card.

Getting help with quote checking

You don't have to do all of this alone. There are three broad options for getting your quotes checked.

DIY checking

For straightforward jobs under £5,000, checking the quote yourself is perfectly reasonable - if you follow a good checklist and know what to look for. The guides linked throughout this article give you the knowledge. You bring the patience and attention to detail.

AI quote checking tools

For projects in the £5,000–£100,000 range - which covers most domestic extensions, loft conversions, and renovations - an AI quote checker gives you a fast second opinion. It'll flag missing scope items, price outliers, and common problems that are easy to miss when you're reading a quote for the first time.

The advantage over DIY is speed and pattern recognition. An AI tool has analysed thousands of quotes and knows what's typically included for each project type. You'd need to research that yourself if going the manual route.

Quantity surveyors

For projects over £150,000, complex multi-phase builds, or formal disputes, a chartered quantity surveyor provides a professional, legally robust opinion. Budget £500–£1,500 for a full review, or £200–£400 for a desktop assessment.

Our comparison of free vs paid quote checking breaks down exactly what you get at each level and where the value lies.

The builder quote checklist

Before you accept any quote, run through this final checklist:

• The document is a quote (fixed price), not an estimate
• It includes a detailed scope of works - not "works as discussed"
• Materials are specified - brands, grades, or quality standards
• Labour and materials are broken down separately
• A start date and completion date are stated
• The payment schedule uses stage payments tied to milestones
• The deposit is no more than 10–15%
• There's a clear exclusions list - you know what's NOT included
• VAT is clearly stated (inclusive or exclusive)
• The builder has confirmed public liability insurance
• There's a process for handling variations (changes to scope)
• The builder's full business name and address are on the document
• You've compared at least three quotes for the same scope
• You've checked the price against regional benchmarks
• You've read the quote line by line, not just the total

If you can tick every box, you're in a strong position. If three or four are missing, go back to the builder and ask for them. If most are missing, find a different builder.

The bottom line

Builder quotes don't have to be confusing or intimidating. The process boils down to five things: get enough quotes, make sure they're detailed, compare them properly, watch for red flags, and protect yourself with the right payment structure.

The cost of getting this right is a few hours of your time. The cost of getting it wrong is thousands of pounds, months of stress, and a project that ends up costing far more than it should.

Start with the basics - make sure your quote includes everything it should. If you've already got quotes and you're not sure whether they're fair, check whether the price stacks up. And if you're staring at three different numbers wondering which one to trust, our guide on comparing quotes properly gives you a structured way to work through it.

Your builder should be your ally, not your adversary. A good quote is where that relationship starts.