The word “architect” is protected by law in the UK — only someone registered with the Architects Registration Board (ARB) can use the title. But that does not mean you always need one. For a significant proportion of domestic renovation and extension projects, an architectural technologist, a draughtsman, or even a specialist design-and-build firm will produce drawings that are equally fit for planning and building control purposes at considerably lower cost.
This guide explains what each professional does, what their drawings actually include, when you genuinely need a registered architect, and what you can expect to pay.
What an Architect Does
A registered architect is trained in the full lifecycle of a building project: concept design, planning strategy, technical design, specification writing, contract administration, and site inspection. Their RIBA qualification (or equivalent European qualification) indicates they have completed a seven-year educational programme and at least two years of practical experience.
For a homeowner, an architect’s key value propositions are:
- Design quality — particularly for complex, unusual, or design-led projects where spatial creativity genuinely matters
- Planning strategy — understanding what a particular LPA is likely to approve and how to frame a scheme to maximise its chances
- Full project management — administering the building contract, certifying payments, and managing the contractor on your behalf
For straightforward extensions and loft conversions, however, the design problem is often not particularly complex, and many homeowners find that a competent architectural technologist delivers what they need.
Architect vs Architectural Technologist vs Draughtsman
| Registered Architect | Architectural Technologist | Draughtsman | |
|---|---|---|---|
| Protected title | Yes (ARB) | MCIAT or TCIAT (CIAT body) | No |
| Training | 7 years minimum | 3–4 years | Variable |
| Design input | Full spatial design | Technical design focus | Primarily drafting |
| Planning drawings | Yes | Yes | Yes |
| Building control drawings | Yes | Yes (often preferred by building control) | Sometimes |
| Contract administration | Yes | Some | Rarely |
| Typical fee (extension project) | 8–15% of build cost or £3,000–£12,000 | £1,500–£5,000 | £600–£2,000 |
When to choose an architect
- The project is design-led (unusual site, conservation area, listed building, contemporary self-build)
- You want contract administration — someone to manage the builder formally on your behalf
- Your LPA has a reputation for design scrutiny and you need a strong design narrative for planning
- The project value exceeds roughly £150,000 and you want a professional accountable under contract
When an architectural technologist is usually enough
- Straightforward rear extension or loft conversion following known typologies
- Permitted development projects where the design parameters are already fixed by regulation
- Budget-conscious projects where the saving of £2,000–£6,000 on professional fees is meaningful
- You are willing to manage the builder yourself
When a draughtsman suffices
- Planning drawings for a simple permitted development project where no building control drawings are needed immediately
- Amendments to existing approved schemes
- Small outbuildings or garage conversions where building control drawings are straightforward
RIBA Plan of Work: The Stages That Matter for Homeowners
The RIBA Plan of Work divides a project into eight stages (0–7). For a domestic extension, the stages you will pay for are:
| Stage | Name | What happens | Typical fee proportion |
|---|---|---|---|
| 0 | Strategic definition | Feasibility, brief, budget check | Included in Stage 1 or free |
| 1 | Preparation & briefing | Surveys, outline design options | 10–15% |
| 2 | Concept design | Scheme design, planning application drawings | 20–30% |
| 3 | Spatial coordination | Technical design, structural coordination | 20–25% |
| 4 | Technical design | Building control drawings, specification | 20–25% |
| 5 | Manufacturing & construction | Site inspections, contract administration | 20–25% |
| 6 | Handover | Snagging, O&M manuals | 5% |
Many homeowners instruct only up to Stage 4 (getting to building control drawings) and then manage the build themselves. This is perfectly reasonable for straightforward projects and reduces fees significantly.
Drawings for Planning Permission
A planning application for a householder extension requires:
- Location plan at 1:1250 (OS-based, available for purchase from Ordnance Survey or the Planning Portal for around £35)
- Site plan at 1:500 showing the existing property footprint, boundary, and proposed extension footprint
- Existing and proposed floor plans at 1:50 or 1:100
- Existing and proposed elevations at 1:50 or 1:100
These are not technically demanding drawings. A capable draughtsman or architectural technologist can produce them to a perfectly acceptable standard. The value an architect adds at planning stage is primarily in design quality and planning strategy, not in the drawings themselves.
Drawings for Building Control
Building control drawings are more technically demanding than planning drawings. They must show:
- Foundation details (depth, width, formation)
- Wall construction and U-values (insulation details)
- Structural information (beam sizes, connection details)
- Drainage connections
- Fire compartmentation and means of escape
- Ventilation and energy performance data
Your architect or architectural technologist produces these drawings in coordination with the structural engineer. Building control then reviews them before approving work on site. An architectural technologist is often more comfortable in this technical environment than a traditional architect whose strength is design.
How to Get a Quote
When seeking quotes, ask specifically what is included:
- How many design revisions are included before additional fees apply?
- Does the fee include dealing with planning queries and resubmissions?
- Are structural coordination and liaison with the structural engineer included?
- Does the fee include building control drawings, or only planning drawings?
- Is VAT included?
Always get quotes from three professionals and ask to see examples of their recent work on similar projects. Check that they carry professional indemnity (PI) insurance — minimum £250,000 of cover for domestic projects.
Key Points
- “Architect” is a protected title; “designer” and “draughtsman” are not. This does not mean unregistered professionals produce inferior drawings — many do excellent work.
- For a straightforward extension or loft conversion, an architectural technologist (MCIAT) typically delivers everything a homeowner needs at 30–50% less than a full architect’s fee.
- The fee split matters: instruct up to building control stage only if you are confident managing the build yourself.
- Always agree in writing what is included, what triggers additional fees, and who owns the intellectual property in the drawings (this matters if you later switch professionals).
