Day rate vs fixed price building work

Day rate building work pays for time: the builder charges for each day on site, and the final cost depends on how long the job takes. Fixed price work pays for an outcome: one agreed sum for a defined scope, however long it takes to deliver. 

The real difference between them isn't the price. It's who carries the risk.

On a day rate, you do. On a fixed price, the builder does. Everything else in this guide follows from that one sentence.

When does a day rate make sense?

Day rates make sense when the work genuinely can't be scoped in advance: exploratory jobs, repairs of unknown depth, and small odd jobs where writing a quote would take longer than the work itself.

Opening up a ceiling to trace a leak is the classic case. Nobody can price what nobody has seen, and a fair day rate is the honest way to pay for discovery.

The going rates are knowable, at least. Across the major trade platforms in 2026, general builder day rates in the UK run from around £150 to £400 per day, with hourly rates of £25 to £60 nationally and £60 to £100 in London and the South East [1].

For a full trade-by-trade breakdown in the capital, our guide to London builder day rates covers what each trade typically charges and what the rate does and doesn't include.

When does a fixed price make sense?

Fixed prices make sense for any project with a definable scope: a bathroom, a kitchen, an extension, a whole-house renovation. If the work can be specified, it can be priced, and a priced project is one you can actually budget for.

A fixed price does something psychological as well as financial.

It aligns everyone's incentives with finishing. The builder profits by working efficiently, not by being present, and you stop doing that quiet daily arithmetic where every tea break has a price tag on it.

Worth knowing: builders price risk into fixed quotes, typically somewhere around 10 to 15% on top of their expected costs, because they're absorbing the unknowns. That premium is real, and it's worth every penny on a big job. You're not paying more for the same work. You're paying someone else to own the downside.

What are the risks of each?

The day-rate risk is drift: no ceiling, no deadline pressure, and a labour bill that grows a day at a time. The fixed-price risk is rigidity: change your mind mid-project and each change gets priced, agreed and papered before it happens.

Worth saying plainly: a builder preferring a day rate for a large, definable project is a small warning sign in itself. It can be innocent. It's also exactly how open-ended jobs are born.

Why do some builders push for day rates on big jobs?

Builders push for day rates on big jobs when they can't or don't want to absorb pricing risk: the scope is vague, the property is unpredictable, or their quoting discipline isn't strong enough to commit to a number.

Sometimes that's rational caution about a genuinely unknowable building.

More often, the vagueness is the problem, not the property. A project without drawings, decisions or a written scope can't be fixed-priced by anyone, and the day rate becomes the default because nobody did the definition work.

There are honest middle grounds too, and it's worth knowing their names. A capped day rate sets an agreed ceiling the bill can't pass. A provisional sum inside a fixed quote ring-fences the genuinely unknown bit (say, £2,000 for whatever's under the floor) while everything else stays fixed. Both give the builder fairness on the unknowns and give you a worst case you can actually plan around.

And if a job starts on a day rate because it had to, convert it once the unknowns are known. Two days of opening up, then a fixed quote for the repair. That sequence is completely normal, and good builders offer it without being asked.

How do you get a fixed price you can trust?

A trustworthy fixed price needs three ingredients: a locked design, a written scope of works, and an itemised quote against both. Give a builder certainty and they can give you a number that holds.

Design is the ingredient people skip.

Every unmade decision, from the tile to the tap to whether the wall moves, is a gap the price can escape through later. It's why Beams locks design before builders quote, and why our interior design service exists inside the process rather than as an optional extra: a fully specified design is what makes a fixed price possible at all.

Then make sure the number you're given is the binding kind. Our guide to the difference between a quote and an estimate shows how to tell a commitment from an educated guess wearing one's clothes.

If you do run day-rate work, keep a site diary. One line a day: who was on site, what got done. It takes thirty seconds, and it's the difference between "it feels slow" and "we're four days over the estimate with the same wall half-built", which is a conversation you can actually have.

How does payment work on a fixed-price project?

Fixed price doesn't mean paid up front. On a well-run project the agreed sum is released in stages as work completes, which keeps the fixed price honest from both directions: the builder is paid promptly for finished stages, and you never have more money out than work done.

On Beams projects that means four milestones (20% at break ground, 30% at first fix, 20% at practical completion, 30% at sign-off), with funds sitting in your Beams account rather than the builder's until you approve each one. The mechanics are all in our guide to milestone construction payments.

Day rate or fixed price, that's the structure that keeps everyone comfortable: pay for what you can see.

Sources

[1] MyBuilder, Builder Day Rate guide (updated May 2026) – general builder day rates of £150–£400; UK hourly rates £25–£60, rising to £60–£100 in London and the South East. https://www.mybuilder.com/handyman/price-guides/builder-day-rate