What is the difference between an architect and an architectural designer?

Architects are registered with the Architects Registration Board and must have completed a 7-year training programme. They can call themselves Architect, which is a protected title. Architectural designers or technicians may have similar practical skills for residential projects but are not registered architects. For standard domestic work, this distinction often matters less than experience with similar projects.

Can I use my own architect with a design-and-build company?

Yes, though it can complicate things. The builder then works from the architect's drawings rather than their own. Issues can arise if the drawings do not match how the builder prefers to work, or if problems emerge mid-build and responsibility is unclear. Some design-and-build firms prefer to use their own designers for this reason.

How do I find a good architect for my project?

Look for architects with experience in your project type like extensions or lofts and in your area since they will know local planning policies. Ask to see similar completed projects. Meet them to check you communicate well—you will be working together for months. RIBA's Find an Architect service is a starting point, but personal recommendations are often better.

Do I Need an Architect for a Home Extension?

Q: Do I need an architect for a home extension?

Not always. There is no legal requirement to use an architect for ordinary domestic work. A straightforward rear, side return, loft or garden room on a house that still has its rights is often handled by a design-and-build team. A listed building, a conservation street, a difficult site, or a planning fight is when a registered architect earns their place. The test is the project, not a rule that every extension needs one. This is not legal advice.

It is a question that comes up early in most extension projects: do you need to hire an architect? The honest answer is "not always"—but knowing when you do and when you do not can save you money and avoid problems later.

Key Takeaways

1
Simple extensions often do not need an architect—a design-and-build firm's in-house team can handle design
2
Complex projects, listed buildings, and difficult planning situations benefit from architectural expertise
3
Architects typically cost between £3,000 and £15,000+ for domestic projects
4
The key factor is project complexity, not a legal requirement
5
Architect is a protected title—only ARB-registered professionals can use it

Short Answer: It Depends on Your Project

There is no legal requirement to use an architect for domestic building work. You could, in theory, draw your own plans and submit them yourself. But the question is not whether you are required to—it is whether your project benefits from professional design input.

For straightforward extensions—rear dormers, simple single-storey rear extensions, garden rooms—an experienced design-and-build company's in-house design team can often handle everything.

For more complex projects—unusual sites, listed buildings, ambitious designs, contentious planning situations—an independent architect's expertise becomes more valuable.

When You Definitely Need an Architect

Consider hiring a registered architect when:

Listed Buildings or Conservation Areas

These projects require careful handling of heritage considerations. Architects experienced in conservation work understand how to satisfy planning officers while achieving what you want.

Complex or Unusual Designs

If you want something architecturally distinctive—not just adding space, but making a design statement—an architect brings creative vision that standard approaches cannot match.

Difficult Sites

Sloping plots, tight access, multiple levels, or unusual building shapes need careful design thinking. An architect can solve spatial puzzles that might defeat standard approaches.

Contentious Planning Situations

If you expect opposition from neighbours or the council—perhaps you have already been refused once—an architect can craft a more convincing application and handle the planning politics.

When a Design and Build Firm Is Enough

For many London residential projects, an experienced design-and-build firm with a good in-house design team is sufficient and often more practical:

Design and Build Works When

Standard extension types like rear or wraparound
Permitted development projects
Budget-conscious projects
You want single point of responsibility

Consider an Architect When

Listed buildings or conservation areas
Complex or unusual designs
Difficult sites with access challenges
You want independent oversight of the build

Expert Tip: If your project is a standard rear extension, side return, or loft conversion in a non-conservation area, a design-and-build firm will almost always be more cost-effective and more efficient than hiring a separate architect. The integrated approach means the people designing your project are the same people who will build it — so there are no translation errors between drawings and construction.

Architect vs Architectural Technician

You will encounter different job titles in this space. Here is what they mean:

Title	Qualifications	Best For
Registered Architect	ARB registered, 7+ years training, protected title	Complex or sensitive projects
Chartered Architect	RIBA member, additional professional recognition	Premium residential and commercial
Architectural Technician	Degree in architectural technology, may be CIAT member	Standard domestic projects
Architectural Designer	Varies—no formal registration required	Check portfolio carefully

For most home extension projects, the practical difference between these professionals is less important than their specific experience with similar projects.

What Does an Architect Actually Do

If you do engage an architect, here is what they typically provide:

Concept Design

Understanding your brief, exploring options, developing the overall design approach

Planning Drawings

Floor plans, elevations, sections, site plans presented to maximise approval chances

Building Regs Drawings

Technical drawings showing construction details, insulation, fire safety, drainage

Specification

Describing materials, finishes, and workmanship standards expected

Tender Management

Sending drawings to builders, managing quotes, helping you compare bids

Contract Administration

Site visits, progress checks, quality assurance, managing variations

How Much Does an Architect Cost

8-15%

Of construction cost

For full service including oversight

Architects typically charge either a fixed fee or a percentage of construction cost. For a £100,000 extension with full service, expect to pay between £8,000 and £15,000.

Expert Tip: If budget is a concern, consider hiring an architect for concept design and planning drawings only, then switching to a design-and-build firm for the construction phase. This gives you the benefit of architectural creativity at the design stage without the higher cost of full architectural oversight during the build.

Fixed Fee Guide

Concept design only: From £1,500

Planning drawings: From £2,000

Full design service: From £4,000

Including contract admin: From £8,000

Our Approach: In-House Design Team

At Trovix, we have an experienced in-house design team that handles most of our projects. Here is why we work this way:

Integration — Our designers and builders work together constantly, so designs are always buildable
Cost efficiency — Design is included in our overall project quote
Single responsibility — We own the design and the build—no gaps or finger-pointing
Local expertise — We know London planning policies, building practices, and what works

For complex projects where you want independent architectural input, we are happy to work alongside your architect. We have collaborated with many London architects successfully.

Wondering what your project needs?

We are happy to advise whether our in-house design team can handle your project, or whether an independent architect would add value. No pressure either way.

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Common Questions