How to Spot a Bad Builder in 30 Seconds

And the one question that will send them running.

Some builders like this building firm talk the talk.
They show up on time, throw around big words, nod at your walls, and promise the world.
But dig a little deeper, and suddenly they go quiet. Or disappear. Or worse—turn your house into a building site that never ends.

You don’t need to be an expert to spot a bad builder. You just need to pay attention.
Because the dodgy ones always give themselves away.

Here’s how to sniff them out—before you hand over a penny.

1. They won’t give you anything in writing

Ask for a written quote and watch their face.

If they start mumbling about “rough figures” or “we’ll sort that later,” walk away.
Good builders are happy to put things in writing. Bad ones avoid it.

Why? Because once it’s written down, they’re committed. And they don’t want that.
They want the freedom to change the rules once the job starts.

Get everything in writing:
– A clear quote
– What’s included (and what’s not)
– A payment schedule
– Timelines
– Guarantees

If they dodge that, they’re dodgy.

2. They ask for a big chunk upfront

A small deposit is normal.
But if they ask for 30% or 50% before they’ve even lifted a spade—alarm bells.

Some builders disappear with your money. Others start strong, then vanish when cash runs out.

You should pay in stages. As work gets done. Not before.

Any builder who pushes for big upfront payments should be treated with caution. Especially if they’re vague about what happens next.

3. They can’t show you previous work

“I don’t have photos.”
“The last client didn’t want me sharing their details.”
“I’ve just started doing this full-time.”

Run.

A proper builder will have:
– Photos of past jobs
– References
– Maybe even happy customers you can speak to

No track record? That is their track record.

4. They say yes to everything

Some builders never say no.
You ask for a bigger window? “Easy.”
You want the job finished in three weeks? “No problem.”
You want to keep the kitchen running through the build? “Of course.”

The good ones ask questions. They look at your space, your budget, your plans—and tell you what will and won’t work.

A builder who says yes to everything without thinking isn’t helping. They’re just trying to win the job. And the problems will come later.

5. They turn up late to the first meeting

If they’re late to quote, they’ll be late to work.

You might forgive traffic once. But if they show up flustered, make excuses, or cancel last minute—it’s a sign of what’s to come.

Reliable builders like Ascent Builders value your time. They turn up when they say they will.
If they can’t manage that for a quote, how will they manage a 6-week build?

6. They refuse to talk about insurance

Ask:
“Are you insured?”

If they say yes, follow up:
“Can I see a copy?”

A bad builder will go quiet. Or say they left it in the van. Or promise to send it later.

That’s your answer.

Public liability insurance and employer’s cover are basic.
If they don’t have it, and something goes wrong—you’re left to pick up the bill.

The one question that sends them running

Here it is:

“Can I speak to your last two customers?”

Not the best one. Not the cousin. Not the mate whose kitchen they did five years ago.
The last two.

Watch what happens.

Good builders have no problem giving you those names. Bad ones will squirm. Stumble. Change the subject. Because they don’t want you finding out what happened last time.

FAQs

What should a builder quote include?
It should break down materials, labour, timelines, and what’s included or excluded. Look for VAT details too—if they say “cash only,” be wary.

Is it okay to ask for references?
Absolutely. Ask for recent ones. And if possible, speak to people who had similar work done.

Should I avoid builders with no website or social media?
Not always. Some excellent builders work on word-of-mouth. But if they’ve got no trace at all—no online presence, no reviews, no cards—ask more questions.

What if the builder’s quote is much cheaper than others?
That’s a red flag. It usually means corners will be cut, or costs will rise later. If it seems too good to be true, it probably is.

How can I check if a builder is legitimate?
Check Companies House. Ask for proof of insurance. Look for online reviews. And trust your gut—if it feels off, it probably is.

Final word

You don’t need a sixth sense to spot a dodgy builder. You just need to pay attention.

The bad ones give themselves away. Late replies. No paperwork. Strange payment requests. And the moment you start asking the right questions—they vanish.

Ask early. Ask often. And remember: the best builders don’t just build well. They’re upfront, honest, and don’t flinch when you ask for proof.