Do I Need an Architect for a House Extension?

  • February 2025
  • Kieron Peaty

If you're planning a house extension, one of the first questions you're likely to ask is: do I need an architect? It's a fair question — and one we hear often. Whether you're adding a rear extension, loft conversion, or opening up the ground floor, the answer depends on what you're hoping to achieve. At Studio 40, we believe good design adds real value. Not just in pounds and pence, but in how your home feels to live in. Here, we explore the benefits of working with an architect, when you might not need one, and what the process typically looks like.

Architect designing house extension

What Does an Architect Actually Do?

An architect is more than just a provider of drawings. Yes, we design spaces — but we also help you think strategically about your home, your budget, and the way you live.

Here are a few of the things we help with:

  • Understanding what’s possible under planning or permitted development

  • Designing light-filled, well-proportioned spaces that feel good to be in

  • Creating drawings for planning, building regulations, and construction

  • Coordinating with structural engineers, consultants, and builders

  • Helping manage the project through to completion

Put simply: we turn your ideas into buildable, beautiful spaces.

 


When You Might Not Need an Architect

Not every project needs full architectural services. If you're doing a straightforward internal layout change, or a basic permitted development extension with a builder you trust, you might choose to work directly with a technician or draftsperson.

However, without design input, you risk missing opportunities to make the space better: more connected, more functional, more joyful.

 


The Value of Good Design

We often meet clients who start out thinking they need "just a box on the back" — but once we show them how light, sightlines, flow and materials can elevate their home, they quickly see the benefit.

Architects:

  • Bring fresh eyes to a tired layout

  • Understand how to make spaces feel generous, not just bigger

  • Know where to invest (and where to save)

A good architect will design around your lifestyle, not just your footprint.

 


What Does It Cost?

Architects usually charge either a fixed fee or a percentage of the build cost. For small to medium extensions, the investment is typically between 8% and 12% of construction costs for full architectural services.

At Studio 40, we also offer phased or tailored services — so you can engage us just for design and planning, or carry through to detailed drawings and on-site support.

 


Do Architects Help with Planning?

Yes. We guide you through the entire planning process:

  • Assessing whether your project qualifies under permitted development

  • Preparing and submitting planning applications

  • Liaising with the local authority

Our designs are sensitive to context, helping improve the chances of approval and neighbour support.

 


How Studio 40 Works

We specialise in residential extensions and new homes across Essex, including Stock, Chelmsford, Brentwood and surrounding villages.

Our approach is:

  • Collaborative — we listen closely before we draw anything

  • Contextual — we design homes that sit comfortably in their setting

  • Calmly modern — our work is light, natural and pared back

We believe architecture should improve how you live, every day.

 


Thinking About Extending?

If you're considering an extension and want to explore your options, we'd love to help.

Contact us to book a consultation or ask a question. We work across Essex and beyond, delivering simple, thoughtful architecture that stands the test of time.

 

We'd love to hear from you.

Book your free consultation to tell us more about your project and to find out how we can help.