Every year, homeowners in Cambridge lose thousands to builders who disappear, do substandard work, or add unexpected costs. Here's how to spot the professionals — and the red flags that signal a builder to avoid.
Red Flags: Signs of a Builder to Avoid
1. No Business Address
If they only give you a mobile number and can't provide a business address, ask why. Reputable builders have premises — even if it's a home office used for admin. Cowboys operate from a van and a phone.
2. Cash-Only or "Discount for Cash"
Offering a discount for cash suggests they're avoiding VAT or tax. That's fine for them, but it means you have no paper trail if something goes wrong. You also have no protection — no contract, no receipt, no warranty.
3. No Written Quote
"I'll do it for about £30,000" isn't a quote. A proper quote breaks down labour, materials, and each stage of work. Without a written quote, you have no way to challenge unexpected costs later.
4. Pressure to Decide Quickly
"I can start next week if you sign today" is a sales tactic, not a genuine opportunity. Good builders are booked weeks or months in advance. If they're desperate for work, ask why.
5. Quotes Significantly Lower Than Others
If one quote is 30%+ lower than the rest, something's wrong. They're either cutting corners, underestimating, or planning to add costs later. Cheap quotes become expensive projects.
6. No Insurance
Ask for public liability and employer's liability certificates. If they're not insured and something goes wrong — a worker injured on your property, a neighbour's wall damaged — you could be liable.
7. No References or Portfolio
Every builder has done "loads of work." But can they show you examples? Can you speak to previous clients? If not, assume they haven't done quality work.
Green Flags: Signs of a Reputable Builder
1. Detailed Written Quote
Breaks down materials, labour, and each stage. Includes a timeline. Shows you exactly what you're paying for.
2. Clear Contract
Includes scope of work, payment schedule, timeline, and how changes are handled. Professional builders use contracts — they protect both parties.
3. Insurance Certificates
Public liability (minimum £2 million) and employer's liability. They provide copies without hesitation.
4. References You Can Contact
Real phone numbers, real addresses. Previous clients willing to talk about their experience.
5. Portfolio of Similar Work
Photos, addresses, before/after shots. Ideally, projects you can drive past or visit.
6. Proper Payment Schedule
Never asks for 100% upfront. A typical schedule: 10% deposit, then stage payments tied to progress.
7. Realistic Timeline
"We can start in 6 weeks and it will take 10 weeks" is honest. "We can start tomorrow and finish in 3 weeks" is suspicious.
8. VAT Registration
If they're VAT registered, they're turning over £90,000+ a year. That's a real business, not a cash-in-hand odd-jobber.
Questions to Ask Before Hiring
- Can I see examples of similar work you've completed locally?
- Can I speak to previous clients?
- Are you fully insured? Can I see certificates?
- What's your payment schedule?
- Will you provide a written contract?
- How do you handle changes during the project?
- What warranty do you offer?
- Who will be on site each day?
How DNDH Measures Up
- ✓ Full public liability and employer's liability insurance
- ✓ Detailed written quotes with payment schedules
- ✓ References from Cambridge homeowners
- ✓ Portfolio of completed extensions, roofing, and renovation work
- ✓ 12-month warranty on structural work
- ✓ Denis or Daniel on site every day