In the UK, someone can call themselves an architect only if they are registered with the Architects Registration Board. The title is protected by law, and using it without registration can lead to a fine of up to £2,500 for each offence.
That makes the first hiring step surprisingly simple: check the register before discussing your kitchen extension, loft conversion or rear addition in detail. Everything else comes after that.
Start with the right kind of professional
An extension may look like a modest project from the pavement. Inside, it can involve planning rules, building regulations, structural changes, drainage, party wall matters, contractor coordination and a long list of decisions about materials and finishes.
You do not necessarily need the most famous practice in your area. You need someone who regularly handles projects similar to yours and understands the type of house you own.
A designer who mainly works on large commercial buildings may be excellent at that work but less comfortable with the practical pressures of a small domestic project. Ask about recent extensions, not just impressive photographs from a portfolio.
Look for examples with a similar scale, age and construction style. A Victorian terrace, a post-war semi-detached house and a modern detached property can create very different design and approval problems. The useful question is not simply, “Do you design extensions?” It is, “Have you solved problems like mine?”
Check ARB registration first
Search for every candidate in the official ARB register. Each registered architect has a unique registration number, and the registration should be current when you appoint them.
The annual ARB registration fee for 2026 is £225, but the important point for a homeowner is not the amount. It is whether the person is currently registered. Ask for the architect’s registration details and check them yourself rather than relying on a website biography or an email signature.
RIBA membership is not a substitute for ARB registration. RIBA is a professional body, while ARB registration is the legal requirement for using the title “architect” in the UK. RIBA does offer a free “Find an Architect” tool, which can help you create an initial shortlist, but each candidate still needs to be checked against the ARB register.
This takes only a few minutes. It can save you from building an important project around a misleading job title.
Build a shortlist of three or four practices
Contacting one practice and accepting its first proposal is tempting, especially when the extension already feels complicated. A shortlist gives you something to compare and reveals how differently architects interpret the same brief.
Send each candidate the same basic information. Include the property address or postcode, the kind of extension you are considering, your approximate budget, any known planning restrictions and your preferred timescale. A few photographs and a rough sketch can be more helpful than a long description.
Do not worry if the design is still vague. “We need a brighter kitchen, a utility area and better access to the garden” is a perfectly useful starting point. A good architect should be able to turn that wish list into questions, options and practical next steps.
Notice the quality of the first response. Is it clear and specific, or does it consist mostly of grand promises? Does the architect ask about your budget and the existing house? Someone who ignores those details before being hired is unlikely to become more organised once work begins.
Ask what the service actually includes
The word “architect” tells you who the professional is. It does not tell you exactly what they will do for your fee.
One architect may prepare an initial design and planning application, then leave you to manage building regulations and the contractor. Another may continue through detailed design, tendering, site visits and contract administration. Both arrangements can be reasonable, but they are not interchangeable.
Ask each practice to describe its service in stages. You might hear terms such as measured survey, feasibility design, planning drawings, building regulations information, technical design, tender support and contract administration. You do not need to memorise the terminology. You do need to know which stages are included, which are optional and which will be handled by somebody else.
For an extension, compare proposals only when they cover the same scope of work. A lower fee may simply reflect a shorter service. If one architect includes planning and technical drawings while another offers planning drawings alone, the two prices are not meaningful rivals.
RIBA indicates that architects commonly offer a broader, complete service on projects from around £50,000 upwards. That does not mean every extension above or below that figure needs the same appointment. It does mean you should ask what level of involvement is sensible for the size and complexity of your build.
Discuss budget before design enthusiasm takes over
Your budget should be part of the first serious conversation. It is not an awkward detail to reveal later, after the architect has developed a beautiful proposal that you cannot afford to build.
Give a realistic figure and say what it includes. Clarify whether it covers construction only or also professional fees, surveys, application charges, structural engineering, VAT and a contingency for unexpected work. If you are unsure, say so. The architect can help separate known costs from assumptions, but cannot protect a budget that has never been discussed.
Ask how the architect’s fee is calculated. It may be a fixed amount, a percentage, an hourly rate or a combination of methods. A fixed fee still needs a clear description of the work it covers. A percentage-based fee needs an agreed basis for the calculation and an explanation of what happens if the construction cost changes.
Be wary of a vague promise to “sort everything out” for a single attractive number. That phrase sounds reassuring until you discover that crucial drawings, site visits or revisions cost extra.
Meet the person who will run the project
A polished practice website does not tell you who will actually work on your extension. Ask who will lead the project, who will prepare the drawings and who will answer your questions.
If the first meeting is with a director but the project will be passed to a junior member of staff, ask to meet that person too. You are not being difficult. You are checking the working relationship before money and time are committed.
Use the meeting to test communication rather than technical vocabulary. Can the architect explain a complicated planning issue in plain English? Do they listen when you describe how the house is used? Do they challenge a weak idea without dismissing you?
The best meeting may not be the most theatrical one. For a home project, patient explanations and prompt, dependable communication are often more valuable than a dramatic concept sketch. I would rather receive a clear answer about a drainage problem than a dazzling mood board that avoids the difficult parts.
Ask for relevant references
Request contact details for recent clients with comparable projects, subject to the practice’s normal privacy arrangements. Ask those clients whether the project stayed close to the agreed scope, how changes were handled and whether the architect remained involved when problems appeared on site.
You can also ask what went wrong. Every building project has surprises. The useful distinction is between a professional who explains a problem, records the decision and manages the consequence, and one who lets uncertainty drift until it becomes an expensive argument.
Planning approval is not guaranteed, even with a strong design. No architect can honestly promise that a local authority will approve every proposal. A responsible professional should explain the likely risks, the relevant constraints and the decisions that may need to change.
Insist on a written appointment
Do not begin on the basis of a friendly email that says the architect will “get started.” Before work begins, ask for a written contract or appointment document.
It should state the exact scope of work, the method used to calculate the fee and the payment milestones. It should also make clear how additional services are charged, how changes to your brief are handled, what happens if the project pauses and how either side can end the appointment.
Transparent fees and written terms are basic checks before hiring an architect. They protect both sides, but they are especially useful to a homeowner who may not commission professional design work often.
Read the exclusions carefully. A proposal might not include structural engineering, measured surveys, specialist reports, planning appeal work, party wall advice, contractor selection or regular site inspections. None of these exclusions automatically makes the appointment poor. They simply need to be visible before you compare the price.
Payment milestones should match actual progress. You should know what you are paying for at each stage and what information you will receive. If the architect requests a large payment before the work is clearly defined, ask why and ask for the arrangement in writing.
Decide who will handle the build
Some architects stop after planning approval. Others help develop technical information, obtain contractor prices and administer the building contract. Your choice affects how much responsibility remains with you.
If you plan to obtain prices from builders yourself, ask whether the drawings and specifications will be detailed enough for a fair comparison. Builders quoting from different levels of information may produce prices that look comparable but cover very different work.
If the architect will visit the site during construction, ask how often, what those visits are intended to achieve and whether they are included in the fee. A site visit is not the same as constant supervision, and the contract should not leave you guessing.
Before hiring, write down the three things that matter most to you. It might be keeping the kitchen in use, protecting the garden, staying within a firm budget or finishing before a particular date. Share that list with the shortlist and see who responds to the real priorities rather than steering the conversation toward their favourite type of project.
The right architect will not remove every risk from an extension. They will make the risks visible early, explain the choices in language you understand and put the agreed work, fees and responsibilities on paper before the first line is drawn.