We've reviewed thousands of complaint files from homeowners. Bad builds rarely surprise you. They announce themselves — in a phrase the builder uses, the homeowner repeats, and three months later regrets.

Here are the twelve we hear most often.

1. "We don't really need a written contract for a job this size."

Every job needs a written contract. A R 300 000 bathroom and a R 6 million home need different contracts, but both need one.

2. "Pay me cash and I'll knock off the VAT."

Walk away. A registered builder cannot legally refuse VAT. An unregistered one cannot legally charge VAT. Either way, this offer is fraud, and the only person exposed is you.

3. "I'll register the home with NHBRC once we get started."

NHBRC enrolment is required before the first stage payment. "Once we get started" usually means "never". If it never happens, your 5-year warranty doesn't exist.

4. "I'm too busy to put the quote in writing. We can shake on it."

A builder who is too busy to write a quote is too busy to build your home. The first contract negotiation predicts the first three months of site behaviour.

5. "My deposit is 40% so I can buy materials upfront."

10% is the market norm. Above 20% is unusual. Above 30% is a financial-distress signal — the builder is using your deposit to finance another job's overdraft.

6. "Don't worry about plans being approved — we'll start, council always catches up."

Council does not always catch up. Building without approved plans is a contravention of the National Building Regulations and can result in a demolition order. The fact that a builder suggests this tells you everything about how they handle other regulations.

7. "Allowance items are just a starting point. We'll work it out as we go."

If your contract says "tiles: R 200 allowance" and you choose R 600 tiles, that is your money. If the builder chooses R 600 tiles and bills you, that is theirs. Specify finishes line-by-line in a schedule of finishes annexed to the contract.

8. "My foreman will handle it. You'll see me at the major milestones."

The named foreman should be in the contract — and the builder should be on site at least weekly. Site visits from the principal are the leading indicator of build quality.

9. "We always get the engineer's certificate at the end."

The engineer signs off at the stage — foundations before backfill, slab before brickwork, roof structure before tiling. End-of-build sign-off is no sign-off at all.

10. "I haven't worked with this team before but they came highly recommended."

The team is the trade. If the bricklayer, plumber and electrician are new to the principal contractor, you're paying for a learning curve. Ask: "Who is your bricklayer? How long have you worked together?"

11. "Snag list? We don't really do that. If something's wrong, just call me."

Snag lists protect both parties. A builder who avoids them avoids the conversation about retention release. Insist on a written snag list at practical completion.

12. "Your retention? Just sign the release — I've never had a defect come back."

The 90-day defects period exists for a reason. Don't release the second half of retention until the period is up and you've walked the building.

If you're hearing more than two of these from your current builder, run our red-flag checklist before signing anything else.