Choosing a builder is one of the biggest decisions in any project. The right team keeps the work organised, the costs clear and the house in good shape. The wrong one can turn an extension or renovation into months of stress. Whether you are planning a kitchen extension in a North Oxford terrace, a refurbishment in Bicester or work on a Cotswold stone cottage, the same checks apply. Here is what to look for.

Be clear about what you need

Before you contact anyone, write down what you want to achieve, any drawings or planning consents you already have, and roughly when you would like the work done. It helps builders give you comparable prices, and it helps you see which ones have understood the brief.

Think about the type of builder, too. A single-trade contractor may suit a small job. A larger project such as an extension, loft conversion or full renovation needs a main contractor who can manage groundworks, structure, roofing, electrics, plumbing, plastering and finishing in the right order. Ask whether the trades are employed in-house or subcontracted. Both can work, but you should know who will actually be on site.

Check credentials properly

Membership and registration claims are easy to make and easy to check:

  • Trade bodies. Organisations such as the Federation of Master Builders, the National Federation of Builders and the Home Builders Federation vet their members. Confirm membership on the organisation’s own website rather than relying on a logo.
  • Gas work. By law, anyone working on gas appliances must be on the Gas Safe Register. Ask to see the engineer’s Gas Safe ID card and check their licence number on the register. The card also shows which types of gas work they are qualified for.
  • Electrical work. Electricians registered with a competent person scheme, such as NAPIT, can self-certify notifiable work under the Building Regulations and issue a certificate when the job is complete.
  • Insurance. Ask for evidence of current public liability insurance and, if the builder employs staff, employer’s liability insurance.

Look at relevant, local work

Oxfordshire has a particular mix of buildings: Victorian and Edwardian terraces and villas, conservation areas across Oxford and market towns, listed buildings and Cotswold stone. Ask to see completed projects similar to yours, ideally nearby, and ask how they handled any surprises. A builder used to period properties will expect to find things like old timber floors, lime mortar and uneven walls, and will plan for them.

Talk to previous clients if you can. Ask whether the work ran to programme, how changes were handled and how tidy the site was.

Compare quotes like for like

Get at least two or three written quotes and read them carefully. A good quotation should:

  • describe the work in enough detail that you can compare it with others
  • say whether it is a fixed quote or an estimate, which may change
  • list provisional sums (allowances for items not yet specified, such as a kitchen or tiles) separately
  • make clear what is excluded, for example decorating, skips, scaffolding or making good
  • state whether VAT is included
  • set out a payment schedule linked to stages of work

Be wary of a price far below the others. It often means something has been left out. Be cautious, too, of requests for a large payment before any work has started.

Ask who handles planning, Building Regulations and party walls

Most extensions and structural alterations need Building Regulations approval, and some need planning permission or listed building consent. Ask the builder how they work with your architect or designer, and who will apply to building control. You can use the council’s building control service or a registered building control approver. A full plans application typically gets a decision within five weeks, or two months if you agree.

If the work affects a shared wall or involves digging foundations close to a neighbour’s building, you will need to serve notice under the Party Wall etc. Act 1996. A good builder will flag this early, because notice periods of one to two months can affect your start date.

Get everything in writing

Use a written contract that covers the scope of work, price, payment stages, start and finish dates, how changes (variations) will be priced and agreed, and how any disputes will be resolved. Some useful protections:

  • Under the Consumer Rights Act 2015, a trader must carry out a service with reasonable care and skill.
  • If you sign a contract in your own home rather than at the builder’s premises, you will usually have a 14-day cancellation period under the Consumer Contracts Regulations.
  • Under the CDM Regulations 2015, the health and safety duties of a domestic client normally pass to the contractor, or to the principal contractor where there are several.

Notice how they communicate

How a builder handles the early stages tells you a lot. Did they visit when they said they would? Did they ask sensible questions about the house and how you use it? Is the quote clear? Ask who your day-to-day contact will be, how often you will get updates, and how the site will be kept safe and tidy, especially if you are living at home during the work.

Warning signs

  • No written quote or contract
  • Pressure to decide quickly or a discount that expires today
  • Cash-only payment or a large upfront deposit
  • No fixed business address or landline
  • Reluctance to show past work or credentials

Working with us

North Oxford Developments has been building in Oxford, Oxfordshire and the Cotswolds since 1984, and we are members of the Federation of Master Builders, the National Federation of Builders and the Home Builders Federation. Our two in-house teams of around 30 qualified tradespeople cover everything from groundworks and bricklaying to roofing, plastering, NAPIT-accredited electrics, Gas Safe registered heating and decorating. Every project starts with a consultation and site visit, followed by a detailed, transparent quotation, so you know exactly what is included before work begins.