Step-by-Step Guide to Starting a Home Extension

Starting a home extension can feel overwhelming – especially if it’s your first major building project.

The good news is that the process is very structured when handled by an experienced builder. At Garnet Construction, we guide homeowners across Hertfordshire and Essex through every stage — from the first idea to completion.

Here’s exactly how it works.

Step 1: Define Your Goal

Before any drawings or quotes, ask:

• Do I need more space or better layout?
• Extra bedroom, kitchen, office, or living space?
• Am I extending to add value or improve lifestyle?

Clear goals = better design + accurate costings.

Step 2: Initial Site Visit & Consultation

A builder will assess:

• Existing property structure
• Available space
• Access for construction
• Feasibility of your ideas
• Rough budget expectations

This is where your vision starts to become realistic.

Step 3: Design & Architectural Plans

Next, you’ll usually work with an architect or designer to:

• Create layout drawings
• Explore design options
• Refine room sizes and flow
• Prepare planning submission drawings

👉 This stage shapes the entire project.

Step 4: Planning Permission (if required)

Not all extensions need planning permission, but many do.

Your plans may be submitted to the local council for approval.

Key considerations:

• Size of extension
• Height and design
• Impact on neighbours
• Property location rules

Approval usually takes 8–12 weeks.

Step 5: Building Regulations Approval

This ensures your extension is safe and compliant.

It covers:

• Structural integrity
• Fire safety
• Insulation standards
• Drainage and electrics

👉 This step is essential for every extension.

Step 6: Detailed Quotation

A proper builder will provide:

• Full breakdown of costs
• Materials and labour
• Timeline estimate
• Payment stages
• Specification details

At this point, you should have a very clear understanding of your investment.

Step 7: Construction Begins

Once approved, work starts on site:

Typical build sequence:

• Groundworks & foundations
• Brickwork / structure
• Roof installation
• Windows & external doors
• First fix electrics & plumbing
• Insulation & plastering
• Second fix & finishing

Step 8: Completion & Handover

The final stage includes:

• Snagging (fixing minor issues)
• Final inspections
• Cleaning and finishing touches
• Handover of the completed space

Your new extension is now ready to use.

Common Mistakes to Avoid

• Starting without clear plans
• Choosing based on cheapest quote only
• Not understanding planning rules
• Making design changes during construction
• Underestimating budget for finishes

Why Work With Garnet Construction?

We specialise in:

• House extensions
• Two-storey extensions
• Loft conversions
• Garage conversions
• Full home renovations

Across Hertfordshire and Essex, we help homeowners turn ideas into well-built, practical living spaces.