The RedBook Guide: How to choose and manage builders and how to avoid building projects running out of control

—31st October 2019

In the second part of our Guide, we explain why a ‘design freeze’ can keep your project on track and on budget, and how to manage your builders if your project starts to run out of control


The simplest, cheapest and most effective way of avoiding a project running over budget or overtime is easy to describe: avoid starting the building work too quickly.

So before you ever engage a builder, be sure to nail down every single detail of the design for the building you wish to create or re-shape. You may be astonished how many questions need to be answered at this stage—the level of detail required to produce a fully complete design specification is almost mind-bending.

But if you can achieve this, and commit yourself to avoid making any changes thereafter (instituting what is known as a ‘design freeze’), you will give yourself the best possible insurance against your project running out of control. This explains why at RedBook we regularly hear leading architects and interior designers urge clients to take their time during the initial design phase of a project.

To be completely frank though, everyone who contemplates a building project has the natural and almost overwhelming urge to get it started and finished as soon as possible, especially if getting planning consent for the building works has taken longer than expected. So it is not everyone who feels able to follow this advice.

And even after you have committed yourself to a design freeze, you have to maintain self-discipline because good ideas don’t stop popping up as soon as the builders start on site. In fact, it is only when the building starts to take shape that you at last begin so see clearly what has actually been designed by your architect, and you may realise belatedly how a detail or a space can be improved.

This realisation comes comes the nagging thought, ‘If we don’t change this now we will be stuck with it forever’. So the temptation to make an unplanned change becomes almost irresistible. But the consequences of making changes once builders are on site are unavoidable: extra cost and delay.

This is largely because builders plan their work in careful sequence. They book their specialist workers well in advance, and these specialists have to finish one task before the next lot of specialists can start work. For example, labourers have to concrete floors before electricians can walk on them to fix their wiring to the walls and ceiling, and the wires in turn have to be fixed before plasterers can fit the plasterboard to the walls—and so on. It is for this reason that making a late change to your design has a compounded knock-on effect on the builders’ schedule.

Be aware, too, that builders tend to charge more for changes—or what they call ‘variations’—during the build than they would have done if the extra work had been included in the original contract.

Sometimes unplanned changes are impossible to avoid even after work on site has started. When you are building on to or adapting a period house rather than knocking a house down and replacing it with a new one, it is all too often the case that builders reveal hidden problems with the structure of the old house once as they start stripping away the paint and plaster. This means some degree of delay and extra cost is unavoidable.


– If unplanned costs are hard or even impossible to avoid, the best way of minimising your stress level is to make sure you allow a sufficient contingency for them in your initial budget for the building project. Professionals differ in their opinions on a sensible size of contingency but 10% is the figure used for many projects.

Do be aware that this does not mean you will avoid spending this extra 10%. Instead, it means that you are extremely likely to spend it but will spend it on things unforeseen at the outset.

– When your architect or interior designer presents you with drawings of the proposed floor plans, showing you how the major pieces of furniture will be arranged in each room, take away the plans and spend some time at home performing this mental exercise: imagine you are walking through the door of each room in turn and doing what you will typically do in the room. So walk into the drawing room, sit on the sofa and look out the window opposite. Or go into your bedroom, walk to your preferred side of the bed, and lie down. Picture in your mind what you will see as you walk, sit or lie there. Take your time doing this.

It is hard work using your imagination like this, but it is tremendously valuable. You may notice that certain dimensions of the room you ‘walk’ through feel uncomfortable, or even spot flaws in the design of the room or the positioning of elements such as doors or windows. If you complete this exercise, you will at the very least avoid unpleasant surprises when the builders actually begin to create the room and thus you will reduce the risk of having to make costly late changes.


How often do you hear about builders finishing a job late? So often it is almost a bad joke.

If you were ever to analyse the minority of projects that did finish on time you would find they share common features, including a design freeze (see above), highly motivated builders and a degree of good fortune—severe bad weather can stymie the best-laid plans on a building site.

But surely there is another way to get builders to finish on time. How about making them pay for delays to make sure they hit their deadline?

Actually, it is a common misconception that builders can be forced to hit their deadlines by imposing brutal penalties on them for every week they are late.

Consider this. A builder who wants to stay in business will avoid signing any contract that imposes huge penalties for late completion. Moreover, good builders are in demand and are often able to pick and choose the projects they work on. A project that carries unusual financial risk is sure to scare them off.

And then there is the law. This prevents you imposing any kind of fine on builders for finishing projects late. Instead, the law only allows you to claim what are called ‘liquidated damages’ from your builders if they breach their contract with you to complete the project on a fixed date.

The amount of these damages is agreed when you sign a contract with the builder. So, if halfway through your project you sense the builder is running behind schedule, you won’t be able to ‘hold their feet to the fire’ by threatening to charge them extra for the delay or by withholding payment.

And the damages that are allowed by law are only those that you are genuinely liable to incur because of the delay: renting alternative accommodation or extra storage space, for example. Many people must wish they could extract payment from their under-performing builder for all the hair they have torn out in frustration as a result of the builders’ delays but, sadly, this won’t wash in law.

There is one last point to keep in mind. If your builder misses the deadline for completing the project, and pays you agreed damages during the weeks of delay, you may well find you need that extra money to pay the fees of the consultants you have engaged—such as your quantity surveyor—for the extra time they are required to work beyond the scheduled end of the project.

So the moral is as clear as day: be sure to choose good, motivated builders in the first place.


Tempting as it is to shout and scream at builders when they fall behind on a promised schedule, it is almost always best avoided. Be direct about your frustration by all means, but treat them professionally at all times. You may end up feeling better for really letting rip at them but to do so risks damaging your relationship with them severely, and most importantly reducing their willingness to work hard and make up for lost time. Think of your builders as being like a sports team: if you can keep them motivated and do your best to boost their morale, they are more likely to deliver winning results. If you become enemies, they will lose heart and do you no favours.

RedBook is a specialist consultancy that helps clients and their advisers select the perfect creative and technical team for significant property projects.

For further information, please contact us on 0207 060 6222. Or email: