Who you need to hire — and in what order

A home building project isn't one hire — it's a small team, brought in over time, each with a job and a moment. Get the order wrong and the costs follow: a builder priced before the design is fixed, a structural engineer engaged after planning has dictated an impossible roof, a party wall surveyor retained the week before work starts instead of months before. This page sets out who does what, when each belongs in the process, and — for the part homeowners worry about most — how to choose a builder you can trust.

Professionals describe the journey in RIBA Plan of Work stages, from strategic definition and briefing, through concept and technical design, to construction, handover and use. You don't need the jargon. In plain terms a domestic project runs: work out what's feasible, design it, get consent, engineer and detail it, agree price and contract, build it, sign it off. The team assembles along that line.

Architect, designer, technologist — the title that's protected

The first hire is usually the person who designs the scheme — and here the words matter legally. "Architect" is a protected title under the Architects Act 1997: only someone registered with the Architects Registration Board (ARB) may call themselves one, and using the title without registration is a criminal offence. A "chartered architect" is ARB-registered and also a member of the RIBA. By contrast, "architectural designer" is not a protected or regulated term — anyone can use it, with or without qualifications or professional indemnity insurance. An "architectural technologist" is different again: a specialist in the technology and construction detail of buildings, with the chartered grade (MCIAT) regulated by CIAT.

The design and consents team — bring in early

• Designer (architect, architectural designer or technologist) — develops the concept, prepares the drawings, and usually runs the planning application. Engaged first, at the feasibility and design stage.
• Planning consultant — for contested, large or policy-sensitive schemes (conservation areas, Article 4, change of use, appeals), a planning specialist strengthens the strategy and the application. Often works alongside the designer from the start.
• Structural engineer — designs the structure: the beams, foundations and load paths that make the design buildable, and produces the calculations building control needs. Bring them in once the design is taking shape, not after it's frozen — the structure can change what's possible.

The statutory and specialist roles

• Party wall surveyor — where the work engages the Party Wall etc. Act 1996 (building on the boundary, excavating near a neighbour's structure, cutting into a shared wall). Notices must be served well before work starts, so engage early; in a dispute, each side's surveyor agrees an award.
• Principal Designer — note there are now two distinct roles with this name. The CDM 2015 Principal Designer coordinates health and safety during design; the separate Building Regulations Principal Designer (under the Building Safety Act, since 1 October 2023) is responsible for building-regulations compliance. Both are required where more than one contractor is involved, and on many domestic projects the designer or contractor takes them on — but the duty to appoint, in writing, is the client's.
• Quantity surveyor (QS) — a cost specialist who prepares budgets, reviews tenders and controls cost through the build. Worth it on larger or higher-value projects where the financial risk justifies it.
• Building control — local authority building control or a private Registered Building Control Approver signs the work off against the building regulations. Engaged before work starts and inspects through to the completion certificate.

The build team — and how to choose a builder safely

The main contractor (builder) is the biggest single spend and the hire that worries people most — rightly, because this is where the cowboy stories come from. We deliberately don't hand you a list of names to trust on faith; we'd rather arm you to judge any builder yourself, which is more honest and more useful. The tools that actually protect you:

• Use the trade-body registers as a filter. Membership of the Federation of Master Builders (FMB), or TrustMark (the government-endorsed scheme), means the firm has been vetted to a standard — not a guarantee, but a sensible starting screen.
• Take up real references. Ask to see two or three completed projects like yours, and speak to those owners. A builder worth hiring will offer this without hesitation.
• Insist on a written contract. For domestic work, use a recognised form such as the JCT Building Contract for a Home Owner/Occupier or the RIBA Domestic Building Contract — not a one-page quote. It sets out price, programme, payments, variations and what happens if things go wrong.
• Control the money. Pay in stages against work actually completed, never a large deposit up front. Hold a retention (commonly around 5%) released after completion and the end of a defects period. Be wary of any builder demanding cash, a big deposit, or full payment before the work is done.
• Confirm insurance and the paperwork chain. The builder should carry public liability insurance, and you should have clarity on who is arranging building control, party wall and the Principal Designer/Contractor appointments.

The order, on one page

How this connects to your Planning Permission Checker report

Planning Permission Checker sits at the start of this chain — the free report tells you what's feasible at an address before you hire anyone, so you brief your designer from facts rather than hope. For the professional steps where a wrong move costs real money — survey, consents and feasibility — enquiries route to Hampstead Chartered Surveyors, an RICS-regulated practice (Firm Reg. 923064). Some projects may also need drawings, planning consultancy, structural engineering, legal advice or other specialist input. For the build itself, we'd rather give you the tools above to choose a builder safely than point you at a name you can't verify.