When planning a house extension, finding a reliable builder is crucial. Ensuring the quality of work and avoiding “cowboy builders” who may leave your project incomplete or poorly constructed is essential. Here are some key points from a recent discussion on how to vet your builder effectively, along with a list of important questions to ask.

Tips to Avoid Cowboy Builders

  1. Personal Recommendations: If you’ve been recommended a builder by someone who has had good work done, this is a great start. Personal recommendations are invaluable because they come from trusted sources with firsthand experience.
  2. Online Reviews: Checking online reviews is another essential step. Look at all the reviews, including video reviews and written comments. Pay attention to patterns of feedback. Consistent positive feedback is a good sign, while recurring complaints should raise red flags.
  3. Check for Continuity: Ensure that the builder follows through on their commitments. Look for evidence of completed projects and satisfied customers. This can help you gauge the reliability and quality of the builder’s work.
  4. Past Work Inspection: If possible, visit past projects the builder has completed. This will give you a clear idea of their workmanship and attention to detail.

The consequences of hiring a poor builder can be severe. As seen in the case of one of the extension project we were brought in on, built by a cowboy builder, the work was left unfinished and poorly executed. We are now tasked with trying to rectify these issues and get the project approved by building control without having to start from scratch.

Key Questions to Ask a Builder

To help you select the right builder for your house extension, here is a list of essential questions to ask:

  1. Can you provide references from past clients?
    • Speaking directly with past clients can give you insights into their experiences and the quality of work.
  2. Do you have a portfolio of completed projects?
    • Reviewing a portfolio allows you to see the range and quality of the builder’s previous work.
  3. Are you fully insured and licensed?
    • Ensuring that the builder is properly insured and licensed protects you from potential liabilities and guarantees that they meet industry standards.
  4. What is your estimated timeline for this project?
    • Understanding the timeline helps you plan accordingly and ensures that the builder can complete the project within a reasonable timeframe.
  5. What is included in your quote?
    • Make sure the quote is comprehensive and includes all aspects of the project, such as materials, labour, and any additional costs.
  6. Do you provide a written contract?
    • A written contract is essential for outlining the scope of work, payment schedule, and other critical details. It serves as a legal safeguard for both parties.
  7. How do you handle unexpected issues or changes to the project?
    • It’s important to know how the builder manages unforeseen problems and whether they are flexible in accommodating changes.
  8. What warranties or guarantees do you offer on your work?
    • Warranties provide peace of mind that the builder stands behind their work and is committed to resolving any issues that may arise post-completion.
  9. Can you provide a detailed breakdown of costs?
    • A detailed cost breakdown helps you understand where your money is going and ensures transparency in the financial aspects of the project.
  10. Who will be managing the project on-site?
    • Knowing who will be directly responsible for the project’s day-to-day management is crucial for communication and accountability.


Selecting the right builder for your house extension involves thorough research and asking the right questions. By following the tips above and using the suggested questions, you can make a well-informed decision and increase the likelihood of a successful and satisfactory project completion. Avoiding cowboy builders and choosing a reputable, reliable professional will ensure your house extension is built to the highest standards.

If you’re looking to build a house extension, please contact us and we can have a discussion.