Once planning permission is in place and your building drawings are underway, the next big question is: who is going to build it? and mostly how to choose a builder for my project?

l straightforward, but it’s one of the biggest risk points in any home renovation or extension project. Get it wrong, and you could face delays, cost overruns, or even legal disputes. Get it right, and your project stands a far better chance of finishing on time, on budget, and with a result you are proud of. 

So let’s look at how to choose the right builder without the guesswork. 

WHY IS CHOOSING A BUILDER IMPORTANT? 

Because no matter how good your drawings are, it’s the builder who turns them into reality. 

And sadly, the residential construction industry is full of: 

• Builders who under-quote to win work, then add “surprise” extras later 
• Firms that overpromise and underdeliver 
• Jobs that run months late because the builder takes on too many projects 
• Poor workmanship that has to be fixed at the homeowner’s expense 
• Disputes over who’s responsible when things go wrong 

Our team has seen all of these first-hand too many times through our career,  even on jobs where planning went perfectly. And we don’t want this to happen to our clients.

When Should I Start Looking for a Builder? 

The best time is once your building regulations drawings are being prepared, and before final construction documents are complete. 

Why? 

• You need technical drawings to get accurate prices 
• Good builders are often booked 2–6 months in advance 
• Early conversations help you assess availability, interest and budget fit 
• Your builder may have useful feedback on timelines or material choices 

Leaving it too late can force you to work with whoever’s available – not who’s best for your project. 

However, thanks to our ongoing relationship with many contractors, we can identify those who could be a good fit for your project and “warm them up” already at planning stage, even asking for an “informal” ballpark estimate of the construction cost.

What Makes a “Good” Builder? 

It’s not just about skills, though those are essential. The best builders are: 

✅ Experienced in your type of project (extensions, lofts, listed buildings etc.)
✅ Properly insured (public liability, employer’s liability, contract works)
✅ Financially stable (so they don’t vanish mid-job)
✅ Organised and communicative
✅ Willing to work to detailed drawings and contracts
✅ Recommended by past clients or architects you trust 

Avoid anyone who: 

🚩 Can start “immediately”
🚩 Doesn’t want to work under a written contract
🚩 Refuses to give references
🚩 Wants cash-in-hand or large deposits upfront
🚩 Isn’t interested in seeing the drawings 

How Can I Find Builders I Can Trust? 

There are a few good routes: 

• Ask your architect:  at Tholos Architects, we only recommend builders we have successfully worked with and trust
• Get recommendations from friends or neighbours with similar work done
• Check professional bodies, like the Federation of Master Builders (FMB) or TrustMark 

Remember: online reviews are helpful, but they can also be misleading. Always ask for real references, call past clients and visit past projects if you can. 

What Should Be in the Quote? 

A serious, professional quote should include: 

• A detailed breakdown of costs, not just one lump sum 
• A clear scope of work based on your drawings 
• Estimated start and finish dates 
• Payment terms (e.g. staged payments, not upfront lump sums) 
• VAT status: some builders aren’t VAT registered, some works may have special VAT rates. Be careful
• What’s included, and just as importantly, what’s not included

Ideally, you should get at least three quotes from suitable builders with similar experience. Your architect can help review them to make sure you are comparing apples with apples!

Also, your architect can provide either a Schedule of Works or Architectural Specifications (or both) during the Technical Design stage to make the tender process of your job as bulletproof as possible.

What Contract Should I Use? 

No building project should go ahead without a contract. Ever. 

For domestic projects, the JCT Homeowner Contract or the RIBA Domestic Building Contract prepared by your architect are both solid options

 In some instances you could have a bespoke agreement – which includes “signing on a quote”, but it is less recommended especially on everything that is not a small job.

A good contract will set out: 

• Payment stages and timing 
• Project timeline 
• Responsibilities of each party 
• Procedures for changes or delays 
• How to handle disputes 

It protects both you and the builder and avoids costly misunderstandings later. 

Should My Architect Be Involved During Construction? 

In many cases, yes, especially for larger or more complex projects.
Our rule of thumb is “definitely yes” for jobs with a Construction Cost estimated over the 100k+VAT threshold, “preferably yes” for jobs with a Construction Cost falling in the range between 50 and 100k+VAT.

An architect can: 

• Administer the building contract 
• Monitor the builder’s progress and quality 
• Certify payments and protect you from overpaying too soon 
• Flag problems before they escalate 
• Keep communication clear between you and the site 

This is called Contract Administration, and it’s often the difference between a smooth build and a stressful one. At Tholos Architects, we offer this service because we know how valuable it is and allows the client to have an extra pair of (expert) eyes throughout the construction process.

Red Flags to Watch Out For 

Be cautious if a builder: 

• Refuses to give written quotes or contracts 
• Keeps changing their price without reason 
• Can’t show insurance or references 
• Tries to pressure you into a quick decision 
• Asks for cash upfront or says “we don’t need drawings” 

Trust your gut, and speak to your architect if anything feels off. 

In Summary 

Feeling Overwhelmed? 

Don’t worry, you are not expected to know (or manage) all of this on your own. 

📞 Book a free 30-minute consultation
We’ll help you understand the builder selection process, recommend reliable contractors, and set your project up for a smooth, stress-free realisation.