Where Do I Even Start With a Home Extension?

Grant Redfern
4 days ago
3 min read

THE HOME EXTENSION SERIES — PART 1

Your step-by-step guide to getting it right from day one.

🌟 INTRO: Not Sure Where To Start With a Home Extension?

If you’re thinking about extending your home, you’re not alone — but it can feel overwhelming at first. Planning rules, drawings, budgets, timelines… it’s a lot if you’ve never done it before.

This guide breaks the process down into simple steps, based on how we walk our clients through a project from first enquiry to breaking ground.

By the end, you'll know exactly where to begin — and what order to do things in.

🧭 1. Start With Your Goals (Not the Design)

Before you look at plans or budget figures, ask yourself:

What problem am I trying to solve?
Do I need more space, or better space?
Is it for family life, work-from-home, resale value — or all three?
What would an ideal transformation look and feel like?

Most great extensions start with clarity, not drawings. Once you know your goals, every decision becomes easier.

🏗️ 2. Speak to an Architect or Design & Build Team Early

If you already know you’re heading towards a bigger change, you have two routes:

➤ Option A — Architect first

Great if you want a detailed design package before approaching builders.

➤ Option B — Design & Build (Architect + Builder together)

This is how we work with Mellor Reid. It keeps design aligned with budget from day one and avoids costly redesigns.

The earlier you involve the right people, the smoother everything becomes.

Myth Buster: You don’t need final drawings to get early budget guidance. A good builder can give realistic ballparks based on your goals.

📑 3. Understand Whether You Need Planning Permission

Not every extension needs planning permission — but many do.

Here’s the quick breakdown:

✔ You may not need planning if:

It falls under Permitted Development
It’s within height, depth and material limits
You’re not in a conservation area

✔ You’ll need planning if:

You’re extending more than permitted
You want a double storey extension
It’s a change of use
Your property has restrictions

If you’re unsure, we or Mellor Reid can check this for you during a free consultation.

💷 4. Budget: What Things Really Cost

This is the part most homeowners worry about — and for good reason.

A realistic budget includes:

Groundworks & foundation requirements
Structural steel
Brickwork & materials
Roofing
Insulation & building regs compliance
Windows & doors (big cost item)
Electrics & plumbing
Finishes
Professional fees

GCR Tip: Always budget 10–15% contingency. Not because things “go wrong”, but because homeowners often upgrade finishes as the vision becomes real.

🧱 5. Timeline: How Long Does It All Take?

Here’s a simple guide:

Design + Planning: 8–14 weeks
Structural & Building Regs: 2–4 weeks
Groundworks to watertight: 3–8 weeks
Internal works: 4–10 weeks

Every project is different, but this gives you a good idea. (We’ll give more detailed timelines in Part 4 of the series.)

🤝 6. Choose the Right Builder (This One Matters)

Look for:

Clear communication
Transparent pricing
Portfolio & client reviews
Regular updates
Insurance & warranties
A structured process (like our GCR onboarding)

You’re trusting someone with your home. Get this part right, and everything else feels easier.

🛠️ 7. What Happens Next?

Once your goals, design and budget align, you’ll move into:

Planning submission (if needed)
Structural design
Agreement of payment schedule
Site start date
Pre-start meeting
Groundworks… and you’re off!

👉 NEXT WEEK:

Part 2 — Do I Need an Architect or a Builder First?

A clear, honest answer that saves you time and money.