Stage Payments Explained: What You Pay, When, and Why It Protects Your Project

You've found the right builder, the design is signed off and the number on the quote is one you can live with. Then comes the question that hardly anyone asks at the first meeting but everyone worries about later: how does the money actually move? On a £300k–£500k extension, refurbishment or new build in Gidea Park, Emerson Park, Shenfield, Hutton or Brentwood, that question matters as much as the design. A clear payment structure is what lets you enjoy the build rather than dread the inbox. Here's how it should work.

Pay for work done, never for promises

The principle behind every well-run premium project is simple: you pay for work that has been carried out, not for work that has been talked about. A modest deposit to secure a start date and cover early ordering is normal. Anything approaching a large percentage up front, before a spade has gone in the ground, is a warning sign, however charming the person asking. A family-run business with a reputation to protect has no reason to ask for it. The rest of the contract sum is released in stages as the project moves forward, so the value sitting in your home always keeps pace with the money you've handed over.

What a stage actually is

There are two common ways a contract breaks the sum down. The first is milestones: fixed payments tied to visible events. On a typical rear or wraparound extension to a 1930s semi in Havering, those might be groundworks complete, structure up and weathertight, first fix finished, second fix finished, and practical completion. You can walk out into the garden and see whether each one has happened before the invoice lands.

The second is regular fixed payments, which is how we currently invoice at SSCS. We take the contract sum and spread it evenly across the build programme, so a £100,000 job running for ten weeks is invoiced at £10,000 a week. The payments track the work as it happens rather than waiting for a big event, which means you never face a sudden £50,000 or £60,000 invoice at the end of a phase. You know exactly what is due and when from the day you sign, which makes budgeting and arranging funds far simpler, and it keeps the site properly resourced week to week because materials and trades are paid for as they are used.

Either way, the schedule should be written into the contract before you sign, with the amounts and timings set out clearly, so there is never a conversation about what is owed halfway through a build.

Provisional sums, contingency and the invoice that shouldn't surprise you

Most surprises on a project come from two words that get skimmed over at quote stage. A provisional sum is an allowance for something that can't yet be priced exactly: the kitchen you haven't chosen, the sanitaryware still on a mood board, the drainage run nobody can see until the old slab comes up. It's an honest placeholder, and a good contractor will tell you when you're heading above or below it before the money is spent.

Contingency is different. It's your own buffer, typically around ten per cent on a refurbishment of an older home, for the things nobody could have known. Keeping it separate from the contract sum means it stays yours if it isn't needed, and if you're borrowing to fund the work, it's worth checking early that the lender's drawdown schedule lines up with your builder's stages. The two don't always match, and finding out at stage three is not the moment.

Retention and the final payment

Towards the end of a project, a small percentage of each payment, usually somewhere between two and a half and five per cent, is held back until snagging is complete and, on many contracts, for a defects period after handover. That is not a sign of mistrust on either side. It gives you a quiet lever if a door needs easing or a bit of pointing needs redoing, and it gives a quality builder the chance to prove that the finish is as good six months on as it was on the day the dust sheets came off. On a premium build, the final payment should feel like the natural close of a good relationship, not a negotiation.

The questions worth asking before you sign

Ask to see the payment schedule alongside the programme, so you can see how the two relate. Ask what happens if a stage slips because of weather, supply or a decision that's taken longer than expected. Ask how variations are priced and agreed in writing before they go ahead. And ask who is coordinating the architect, structural engineer, party wall surveyor and specialist trades, because when one team is your first point of contact for all of it, the payment structure tends to be clearer too. As a design-and-build contractor, we handle that coordination from the first conversation, which is exactly why our clients rarely have to ask where the money went.

Craftsmanship you can see, and pay for as it appears

A well-structured payment schedule is one of the least glamorous parts of transforming a home, and one of the most reassuring. It turns a large number into a series of moments where you can stand in your own house, see the progress, and know that the quality you're paying for is the quality you're getting.

If you're planning a dream project in Gidea Park, Emerson Park, Shenfield, Hutton, Brentwood or anywhere across Havering and East London, we'd be glad to walk you through how we structure a build from first sketch to final snag. Talk to the Smith & Sons team about your project, and let's plan it properly from the start.

Built on excellence. Driven by family.