Do I Need an Architect for My Home Extension Project?
No, UK law does not require you to hire a registered architect for a home extension. You are legally free to use an architectural technician, a design and build company, or in some cases your builder’s in-house designer. Whether that is the right decision depends on the complexity of your project, whether you need planning permission, and how much you want to maximise the design of the space.
What Is the Difference Between an Architect and an Architectural Technician?
A registered architect holds a qualification recognised by the Architects Registration Board and is bound by a statutory code of practice. Only someone registered with the ARB can legally call themselves an architect in the UK.
An architectural technician produces technical drawings and handles building regulations submissions but is not ARB-registered. Their fees are typically 20% to 30% lower than those of a qualified architect. For straightforward extensions with standard layouts, an architectural technician is often sufficient.
Design and build companies often include a design service within their overall contract price. This works well for homeowners who want a single point of contact, provided the design offer covers what the project actually needs.
When Do You Need a Registered Architect?
A registered architect adds the most value on projects that require creative problem-solving, complex planning applications, or work on listed buildings and conservation area properties.
If your extension involves an unusual site, significant structural changes to the existing building, or a design that needs to satisfy a demanding planning officer, the experience of a registered architect is more likely to get the outcome you want.
For a straightforward single-storey rear extension on a standard semi-detached or detached property without planning complications, a registered architect is not essential. An architectural technician or experienced design and build company can handle the drawings and building regulations submission competently.
What Does an Architect Actually Do on an Extension Project?
The scope of an architect’s involvement varies and this affects the cost significantly. Most architects offer services across several stages.
At the design stage, they produce measured surveys, concept designs and planning drawings. At the technical stage, they produce detailed drawings for building regulations. At the construction stage, they can make site visits to check quality and deal with queries from the builder. Full project management, where the architect manages the builder directly on your behalf, is also available but adds considerably to the fee.
You do not have to use an architect for all of these stages. Many homeowners appoint an architect for planning drawings only and then manage the building regulations and construction stages themselves or through their builder.
How Much Do Architects Charge for an Extension?
According to the HomeOwners Alliance, UK architects typically charge between 3% and 15% of total construction costs. The wide range reflects differences in project complexity, the architect’s experience, their location and the level of service involved.
For full architectural services on a home extension, most practices charge between 7% and 12% of the construction cost according to data from dRAW Architecture and Design for Me’s 2025 survey. On an £80,000 extension, that is £5,600 to £9,600. On a £150,000 project, fees for a full service run from £10,500 to £22,500.
Fixed fees for planning drawings only, without ongoing site involvement, are available from some practices and online architectural services, typically starting from £1,500 to £4,000 for a straightforward extension.
Do You Need an Architect to Get Planning Permission?
No. Planning applications can be submitted by the homeowner, a builder, an architectural technician or any other person. The application is assessed on its merits regardless of who prepares it.
That said, a poorly prepared planning application costs time and sometimes money if amendments are required. For applications in conservation areas, on listed buildings or for designs that push permitted development limits, professional preparation materially improves the outcome.
What Does Use Your Space Provide in Terms of Design?
Use Your Space manages the full process for extension projects across Solihull and Warwickshire, including design, building regulations, structural coordination and construction. We work with architectural technicians and structural engineers as part of our process and can advise you on whether your specific project warrants appointing a registered architect based on the planning and design requirements involved.
Frequently Asked Questions
Is it a legal requirement to use an architect for a home extension? No. UK law does not require homeowners to appoint a registered architect for a home extension. You can use an architectural technician, a design and build company or an online drawing service.
What is the difference between an architect and an architectural technician? A registered architect is qualified and regulated by the Architects Registration Board. An architectural technician produces technical drawings and handles building regulations but is not ARB-registered. For most standard extensions, an architectural technician is sufficient.
How much does an architect charge for an extension? Between 7% and 12% of construction cost for a full service, according to 2025 industry data. On an £80,000 extension that is £5,600 to £9,600. Planning drawings only, without site involvement, typically start from £1,500 to £4,000.
Do I need an architect if my extension is permitted development? Not necessarily. If your extension qualifies as permitted development and does not require a planning application, the design work needed is primarily technical rather than creative. An architectural technician or design and build company can usually handle this.
When is it worth paying for a registered architect? On complex or unusual projects, listed buildings, conservation area properties, or where you want to maximise the design quality of the space. For a straightforward single-storey rear extension on a standard property, it is often not necessary.
Use Your Space manages extensions from initial design through building regulations, structural engineering and construction across Solihull, Warwick, Knowle, Dorridge, Bentley Heath, Shirley, Balsall Common, Leamington Spa and Kenilworth.
Contact Use Your Space today to discuss your project.
