A loft conversion should be exciting. More space, better layout, and a chance to add real value to your home.

But that dream can quickly turn into a nightmare if you pick the wrong builder.

Sadly, there are still plenty of so-called professionals out there who talk the talk, take your deposit, and leave you with half-built messes, leaking roofs, and excuses. These are the cowboys — and they’re more common than you think.

Here’s how to spot them before they ruin your loft and cost you a fortune to put things right.

1. No Paper Trail

A builder who says “you don’t need a contract” is one you should walk away from.

Verbal promises are worth nothing when things go wrong. A proper builder will give you a written quote, a clear scope of work, and some form of agreement that protects you both.

If they dodge paperwork or say “it’s all trust,” that’s a warning sign.

2. Pressure to Pay Upfront

It’s normal to pay a small deposit before work starts — especially if materials need to be ordered. But if they ask for a large lump sum upfront or want full payment in cash before the job begins, alarm bells should ring.

A reputable builder in Kent will offer a staged payment plan. You pay as the work progresses, not before anything’s even started.

3. No Portfolio, No Reviews

Any good builder will be proud to show off past work. They’ll have pictures, reviews, or even previous customers you can speak to.

If they avoid the subject or say, “I don’t take photos,” that’s usually because they don’t want you to see the results.

Google them. Check social media. Ask around locally. If nothing shows up — or what you do find is worrying — walk away.

4. Vague Answers About Timelines

A loft conversion isn’t a five-minute job, but you should still be given a rough timescale.

Cowboy builders tend to be vague — or worse, they promise impossible deadlines to win your trust. Then the excuses start.

Weather. Delays. Van trouble. You’ve heard it all before.

Ask for a written schedule with realistic start and finish dates. If they can’t provide that, it’s not a good sign

5. No Insurance or Guarantees

Proper builders have insurance. That includes public liability (to cover damage to your home) and often structural warranties on their work.

If your builder can’t provide insurance details or shrugs it off, that’s risky. If something goes wrong, you could be left with the bill.

6. Always “Available Now”

If a builder says they can start immediately — especially during peak season — be careful.

Good loft conversion companies in London are usually booked for weeks or even months. A diary that’s wide open could mean they’ve just been kicked off someone else’s job… or have no work lined up for a reason.

7. Won’t Deal With Building Control

All loft conversions must follow building regulations. That includes insulation, structure, fire safety, and access.

Cowboys often try to skip this by saying you don’t need it, or that they’ll “sort it later.”

They do this to avoid inspections — which would reveal poor work. Don’t fall for it. A builder who doesn’t involve building control is cutting corners.

8. Too Good to Be True Quotes

You get three quotes. Two are in the same ballpark. The third is much cheaper. Tempting, right?

That’s the trap. Cowboy builders undercut others to win the job, then make up the difference with cut corners, shoddy work, and extra charges later.

If something looks too cheap, there’s usually a reason

9. Poor Communication from Day One

If they turn up late to the quote appointment, don’t answer calls, or take days to respond to messages, expect more of the same once the job starts.

You’ll end up chasing them every week — while your loft sits unfinished.

10. Gut Feeling

Trust your instincts. If something feels off, it probably is.

Maybe they’re too smooth. Maybe they avoid questions. Maybe they’re friendly but just a bit too casual about big details.

Don’t ignore those little warning signs. They usually turn into big problems later.

Final Word

A loft conversion is a big project. Get it right, and you’ll gain extra space and value. Get it wrong, and you could end up paying twice to fix a disaster.

Take your time. Ask questions. And never be afraid to walk away if things don’t feel right.

Because once a cowboy builder is in your home, getting rid of them — and undoing the damage — is far harder than spotting the signs early.