Guides · 2 October 2026 · 5 min
Do I need an architect for an extension?
Not legally. Here is what a good architect or architectural designer changes, and when it matters most.
There is no legal requirement to use an architect for a house extension in the UK. Many extensions are drawn by technicians or builders. The question is what you gain by appointing an architect, and whether it is worth it for your project.
Only people registered with the Architects Registration Board can call themselves architects. Architectural designers, like NDB Architecture, offer design and drawing services without the protected title. Choose on the quality of work, local experience and clarity of the proposal.
Layout before floor area
A good designer looks at the whole house, not just the new room. Often the best outcome comes from reorganising the existing plan as much as from building out. That is where most of the value lies.
Planning risk
In conservation areas, on listed buildings or where permitted development is uncertain, an experienced designer reduces the risk of refusal and knows when pre-application advice is worth the time.
Information for your builder
A complete set of drawings and a specification means builders price the same job. That makes quotes comparable and reduces variations on site.
When you may not need one
A simple single-storey extension to a modern house, outside a conservation area, with a clear brief, can be well served by a planning and building regulations drawing service.
Related service: House extensions
