Whether it is an extension, loft conversion, or renovation, it is important that your builder has the right skill set and experience
to deliver what you expect. Therefore, it is vital that you ask how many similar projects they’ve undertaken. At the same time, ask if you can see evidence of previous projects and quite possibly whether they have any similar works going on currently and whether they are happy for you to visit the site. A quality builder should have plenty of case studies they are willing to share with you and if they value you, as a customer, and their relationship with you, they should be happy to show you how they operate.

If your builder is a member of a trade body – look for the Federation of Master Builders (FMB). The FMB has a code of practice with stringent membership criteria, including solvency and safety, so membership is a good indication you’re picking a reliable and trustworthy professional.

Whilst previous case studies can give you an overview of their experience, there is nothing quite like direct feedback from previous clients and a good builder will happily provide contact details of previous clients (only when permission to do so has been provided by our client) Give them a call and ask about their experience of working with the builder, particularly around the timescales for the project, the quality of communication, disruption during the build and final quality of the work itself.
It is always worth checking third-party reviews as well, though these may not always be available. Whilst a can control what reviews it wants to put on its own website, it can’t control the feedback to independent websites like Google, Rated people, and Facebook.

Make sure you are clear about what you are getting from your builder. An estimate is, what it says just an estimate, and it’s not binding. If you rely on this from a builder, you risk the final costs being significantly different from the original number provided.
A quotation, on the other hand, should be a fixed price to complete a job. This should be based on an agreed Scope of Works (SOW) specification, drawings (or stated if not required), and delivered for the stated price. The quotation should include all of the work to be done that has been agreed by you and is outlined in the detailed SOW, including items such as cleaning up the site at the end of the job, removal of rubbish during the job and even specifying ensuring the windows, cabinets carpets, etc are professionally cleaned before the job is considered as completed.

Ideally, your job will run smoothly, however, a building site can be hazardous and things can go wrong. If they do, it’s good to know that your builder has been prepared. Ask for confirmation that your builder is properly insured and that you see evidence that they have both public and employers liability insurance – A good builder will have no problem providing their certificates as evidence.

Be very wary of a builder asking for large payment upfront. Some might require immediate payment to cover materials, though conversations with previous clients should help verify if this is standard practice. Beyond this initial payment, usually between 10 – 20 % for materials, however, a reputable builder should agree on a schedule of staged payments throughout the project. You can ask this to be documented, based upon what is agreed upon before work commences.
In addition, you should confirm, and ask the builder to document, that you will withhold an amount (usually 10% of the fee) from the final balance. This will only be paid upon satisfactory completion of the project. Before completion of the project, you should review the work and record details of all the work that is not completed or is below standard. These snags will need to be completed and agreed upon as completed by you before the snag payment is released.

In allowing a builder to work on your property, trust and communication are essential for the smooth running of the project. Whilst the builder will be doing the work and you may not understand the details, you need clear and regular communication about progress, any issues that might arise, and any potential delays. There is nothing quite as frustrating as an unresponsive builder, so make sure you have a clear, agreed process for updates and an agreed turnaround time on queries.

It is essential that you agree on a start date and timescale for your project. Building work, particularly in your own home, can be a major upheaval to your domestic living arrangements and an inconvenience to you and your family whilst going on. Getting geared up for a project to begin only for a builder to say they need to delay it, will do little to smooth the process.
A good builder may have a long lead time before they can start your project, whilst you, as a client, are likely to want the work as soon as possible. Don’t think that the right builder is the one that can start the quickest as some companies will give you a quick start date in order to win your work.
Instead, make sure the start date is realistic. Ask about the other projects they have on currently and choose your builder based not on who can start the soonest, but rather on a combination of who can give you a detailed plan for the project, provide an estimated, and realistic, start and finish date and who seems willing to support you and provide good answers to the questions above.