Planning Your Home Extension: 5 Things You Must Know

Posted on by

Introduction

Planning your home extension can be exciting—but without the right advice, it can also feel overwhelming. Whether you’re creating space for a growing family or upgrading for energy efficiency, it’s essential to understand the full picture before diving in.

As an Architectural Technician, I guide homeowners through every step, from idea to build. This post shares five must-know tips that will help you plan confidently, stay on budget, and create a design that works now and in the future.

1. Planning Your Home Extension Requires the Right Design Process

Before any work starts on site, the design phase is where success is built. It includes:

  • A measured survey to record your home

  • Concept drawings to explore ideas

  • Planning drawings for your local authority

  • Building Regulations drawings to meet safety and energy standards

Working with an Architectural Technician ensures each stage is tailored, practical, and in line with both your budget and goals. You’ll get a design that works in real life—not just on paper.

Learn more about the architectural design process from RIBA

2. Know the Planning Permission Rules in Advance

Many homeowners are surprised by how quickly rules can limit their plans. Depending on size, location, and type of property, you may need full planning permission.

An experienced technician can help you:

  • Check if your idea falls under Permitted Development

  • Navigate local planning policy

  • Prepare a strong application with clear drawings

Expect around 8–10 weeks for a decision, so build that into your schedule early.

Visit the UK Planning Portal

3. Budget for the Whole Journey

When planning your home extension, think beyond bricks and labour. A complete budget includes:

  • Professional fees (design, engineers, planning)

  • Planning and building control costs

  • A 10–15% contingency

  • Extras like rooflights, sliding doors, or insulation upgrades

Clear designs lead to accurate builder quotes—helping avoid budget blowouts later.

4. Future-Proof Your Design for Life Changes

Designing just for today can lead to regrets tomorrow. Smart home extensions adapt to how life evolves.

Ask yourself:

  • Will the layout work with older teens or guests?

  • Is there scope to add solar panels or MVHR later?

  • Could rooms serve different purposes down the line?

We can even design with PassivHaus principles in mind, giving you better comfort and lower energy bills.

Learn more at the PassivHaus Trust

5. Timelines Matter – So Start Early

Homeowners often underestimate how long things take. Even smaller extensions can involve:

  • 1–2 months for design

  • 1–2 months for planning

  • 4–6 months for construction

Getting a head start means you won’t feel rushed or make snap decisions. A calm, planned approach always leads to better results.

Conclusion

Planning your home extension is a chance to create something truly special. With the right advice, a clear process, and thoughtful design, it can improve how you live for years to come.

Let’s create a home that grows with you—sustainably, beautifully, and stress-free.

If you would like to talk to me about your project, use the contact form today.