My Builder Wants 50% Deposit - Is That Normal?

No. A 50% deposit is not normal. If your builder is asking for half the project cost before they've lifted a finger, that's a serious red flag. The standard deposit for building work in the UK is 10–15% of the total cost. That's it.

Let's talk about what's reasonable, what's not, and how to protect yourself.

What's a normal deposit for building work?

For most residential building projects - extensions, loft conversions, renovations - a deposit of 10–15% is standard. This covers the builder's initial costs: ordering materials, booking subcontractors, and reserving your slot in their schedule.

On a £60,000 extension, that means a deposit of £6,000–£9,000. Not £30,000.

Some builders ask for nothing upfront. They fund the first stage themselves and invoice you at the first milestone. That's perfectly normal too - it just depends on how the builder runs their business.

When a higher deposit might be justified

There are a few situations where a deposit above 15% can be legitimate:

• Bespoke or made-to-order items. If your project includes a custom kitchen, bespoke joinery, or specialist materials that need to be manufactured, the supplier may require payment upfront. A builder might ask for 20–25% to cover these orders. That's understandable - but they should show you the supplier invoices.
• Very small jobs. On a £3,000 bathroom refit, a 10% deposit is £300. Some builders will ask for a larger percentage on small jobs because the materials cost makes up a bigger share of the total. A 25% deposit on a small job isn't unreasonable.
• Specialist trades. Steelwork fabricators, glass manufacturers, or stone suppliers often need payment before delivery. Again, your builder should be transparent about why the deposit is higher and where the money is going.

But even in these cases, 50% is too much. If they need more than 25% upfront, ask to see the supplier invoices that justify it.

Why a big deposit is risky for you

Here's the blunt version: if your builder goes bust or walks off the job, your deposit goes with them.

You'd be classed as an unsecured creditor. That means you join the queue behind HMRC, the bank, and anyone else the builder owes money to. In practice, unsecured creditors rarely see a penny back.

The bigger the deposit, the more you stand to lose.

There's another problem too. A large upfront payment removes the builder's financial incentive to finish the work. When they've already got half the money in their account, the urgency to crack on drops. Jobs that should take ten weeks start drifting to fourteen. Then eighteen. You've got less leverage because you've already paid. If you've already paid and your builder hasn't started work, you have options.

Compare that to stage payments (more on those in a moment). With stage payments, the builder earns money as they complete work. They're incentivised to hit milestones because that's when they get paid. That alignment of interests is exactly what you want.

Red flags around deposits

Watch out for these warning signs:

• "I need the money to buy materials." A legitimate builder has trade accounts with suppliers. They don't need your cash upfront to buy bricks and cement. If they can't get trade credit, ask yourself why.
• "We're very busy and need to secure your booking." A 10% deposit secures a booking just as well as a 50% one. If they need more than that to "hold your slot," something doesn't add up.
• Cash only, no receipt. If they want a large deposit in cash with no paperwork, walk away. We cover this in more detail in our post on whether you should pay your builder in cash.
• No written contract or payment schedule. A builder asking for a large deposit without a written agreement is asking you to trust them with a lot of money and no legal protection. Don't do it.
• Pressure to pay quickly. "If you can transfer it today, we can start next week." Legitimate builders give you time to review the contract and payment terms. Pressure to rush is a red flag.

If your builder's quote is triggering alarm bells, check it against the full list in our guide to what a builder's quote should include. A proper quote will have clear payment terms - including the deposit amount and stage payment schedule.

How stage payments work

Stage payments (sometimes called progress payments) are the industry standard for residential building work. Instead of paying a lump sum upfront, you pay in instalments tied to completed milestones. Our guide to stage payments and retention explains the standard structures in full detail.

Here's a typical stage payment schedule for a single-storey extension:

The exact percentages vary, but the principle is the same: you pay for work that's been done, not work that's been promised.

Notice that the builder never has more than 10–15% of your money ahead of the work. If they walk off the job at wall plate level, you've paid 40% and you've got 40% of the work done. That's fair.

With a 50% deposit, if they walk off at the same stage, you've paid 50% and got 40% of the work done. You're £6,000 out of pocket on a £60,000 job - with no easy way to recover it.

The retention trick

Some homeowners hold back 2.5–5% of the total as a "retention" - a final payment that's only released once all snagging items (the small defects and unfinished bits) are fixed. This gives you leverage to make sure the builder finishes properly rather than rushing off to the next job.

Not all builders agree to retention, but it's worth asking. It's standard practice in commercial construction and there's no reason it shouldn't apply to your kitchen extension too.

What to do if your builder insists on 50%

Step 1: Ask why. There might be a legitimate reason. Maybe there's a £15,000 bespoke kitchen order that needs paying upfront. If so, ask to see the supplier quote and offer to pay the supplier directly.

Step 2: Propose stage payments. Show them a stage payment schedule like the one above. Most builders will accept it. If they've never used one before, that tells you something about how they run their business.

Step 3: Get it in writing. Whatever you agree, put it in the contract. The payment schedule, the milestone definitions, and what happens if the builder doesn't hit a milestone on time.

Step 4: If they won't budge, walk away. A builder who insists on 50% upfront, won't explain why, and won't accept stage payments is either in financial trouble or planning to take advantage. Either way, you don't want to be their customer.

How to protect yourself long-term

• Always pay by bank transfer. It creates a paper trail. Never pay large sums in cash - you'll have no proof of payment if things go wrong.
• Keep a copy of every invoice and receipt. Even the small ones.
• Check the builder's credentials before paying anything. Companies House registration, public liability insurance, trade body membership (FMB, Checkatrade, TrustMark). A quick check now saves a lot of pain later.
• Use a written contract. The FMB and JCT both publish homeowner-friendly building contracts. They're not expensive and they protect both sides.
• Check your quote isn't missing things. A large deposit stings even more when the builder later says building regs or scaffolding weren't included. Make sure you know the full cost before committing - our post on quotes missing building regs covers one of the most common gaps.

If you're comparing quotes and want to check whether the payment terms are reasonable, upload your quote to MyBuildAlly. We'll flag anything unusual - including deposit amounts that are higher than they should be.

Before you sign anything, it's worth checking for other signs your builder might be overcharging. A big deposit is often just one of several warning signs.

The bottom line

A 10–15% deposit is normal. Up to 20–25% can be justified for bespoke orders. Anything above that should make you pause. And 50%? That's not a deposit - that's a loan to your builder with no interest and no guarantee you'll get it back.

Pay in stages. Keep the receipts. And if something feels off, trust your gut.

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