Cost Factors to Consider When Having a Home Extension Done in Edinburgh

If you’re thinking about adding more space to your home, an extension is often the best way to do it. Whether it’s to create a bigger kitchen, an extra bedroom, or open up the back of your house for more light and flow, a well-planned extension can transform how you live — and add real value to your property.

But before you get started, it’s worth understanding the main cost factors that come into play when building an extension in Edinburgh. Every project is different, but a few key things will always affect the overall price.

1. Size and Type of Extension

It might sound obvious, but the size and style of your extension have the biggest impact on cost. A simple single-storey rear extension is usually the most budget-friendly option, while double-storey or wrap-around extensions naturally cost more due to extra materials, structure, and labour.

Even within a single-storey design, factors like ceiling height, glazing, and roof type (flat vs pitched) can influence the total spend.

Typical costs:

• Single-storey extension: £2,000 – £2,800 per m²

• Double-storey extension: £2,500 – £3,500 per m²

• Garage or basic rear extension: £1,800 – £2,200 per m²

  
  

Adding features like bi-fold doors, skylights, or bespoke roofing can increase these figures, but also greatly improve natural light and space.

2. Ground Conditions and Foundations

Edinburgh’s mix of old stone buildings and sloping plots means ground conditions can vary a lot. If your site needs deeper foundations, retaining walls, or structural support, costs will rise. A site survey carried out early can help identify potential challenges before work begins — saving both time and money later.

Typical costs:

• Standard strip foundations: £120 – £200 per m²

• Reinforced/deep foundations: £250 – £400 per m²

• Site prep and drainage: £1,000 – £3,000

3. Materials and Finishes For A Home Extension

The choice of materials can make a huge difference. Brick, render, stone, cladding, or timber all come at different price points. The same goes for internal finishes — flooring, tiles, kitchen fittings, and lighting.

If you’re going for a modern look that blends old and new (a common trend across Edinburgh renovations), consider where to spend and where to save. A builder or architect can help you balance design and budget effectively.

Rough guide:

• Basic materials: affordable and practical

• Mid-range finishes (brick, slate, timber): +10–15%

• Premium finishes (stonework, aluminium glazing): +20–30%

  
  

For internal finishes:

• Kitchens: £5,000 – £20,000+

• Bathrooms: £4,000 – £10,000

• Flooring & paintwork: £30 – £80 per m²

4. Design and Planning Costs

Working with an architect in Edinburgh will add design fees, but it’s often worth it. A well-thought-out plan can make your extension flow better, comply with local planning regulations, and even reduce construction costs by avoiding on-site changes.

Depending on the scale of your project, you may also need:

• Planning permission or a certificate of lawful development

• Structural engineer drawings

• Building warrant approval

  
  

These professional fees are part of the total construction cost and shouldn’t be overlooked.

Architect fees:

• Usually 5–10% of total build cost

• Or around £1,000 – £3,000 for a straightforward extension

You’ll also need a structural engineer to produce drawings and calculations:

• Simple beam calculations: £500 – £1,000

• Full structural drawings: £1,000 – £2,500

  
  

Planning permission and building warrant:

• Planning application: £300 – £600

• Building warrant: usually 1–2% of project cost

Additional costs if tree surveys, bat surveys etc are required.

5. Services, Heating & Electrical Work

When extending your home, existing systems like plumbing, heating, and electrics often need upgrading or rerouting. Underfloor heating, additional radiators, or new circuits can add to the price, especially if the original setup can’t handle the extra demand.

It’s also worth considering energy efficiency improvements while work’s underway — things like better insulation, LED lighting, or upgraded glazing can make a long-term difference to running costs.

Average costs:

• Plumbing & heating: £2,000 – £6,000

• Electrical work: £2,000 – £5,000

  
  

6. Access and Site Conditions

If your property is on a tight Edinburgh city street or surrounded by other buildings, access for machinery and deliveries might be limited. This can slow down progress or require more manual work, which adds to labour costs. Good planning upfront helps avoid delays once construction starts.

7. Finishing Touches and Landscaping

Once the build itself is done, you’ll still want to think about finishing touches — painting, flooring, and garden areas that connect nicely with your new space. Many homeowners forget to include landscaping in their budget, even though it can make a big difference to how your extension feels once complete.

Typical landscaping costs:

• Patio or decking: £80 – £150 per m²

• Turfing or planting: £30 – £60 per m²

8. Choosing the Right Builder

Finally, one of the most important factors is who you choose to build it. A reliable, experienced builder in Edinburgh will make sure the work is done to a high standard, on schedule, and within budget. It’s worth checking previous projects, reviews, and making sure they’re open about costs and timelines from the start.

Example: Typical 25m² Extension in Edinburgh

Here’s a quick idea of what a small to mid-sized single-storey extension might cost overall:

Item	Estimated Cost
Architect + Engineer + Planning	£1,000 – £3,000
Foundations & Groundworks	£5,000 – £8,000
Main Build (Structure, Roof, Windows)	£40,000 – £60,000
Plumbing + Electrical	£4,000 – £8,000
Finishes (Kitchen, Flooring, Paint)	£10,000 – £15,000
Landscaping	£2,000 – £4,000
Total (Approx.)	£60,000 – £100,000

Always add 10–15% contingency for unexpected costs, and remember VAT at 20% will usually apply.

Ready to Start Planning Your Extension?

Every home and every project is different, but understanding these cost factors will help you plan with confidence. At LBSC Ltd, we handle extensions, loft conversions, renovations, and full construction projects across Edinburgh — from the first discussions to the final finish.

If you’d like to chat about your ideas or get a clearer picture of what your project might cost, get in touch:

📞 0131 2100 148📧 hello@limitlessbsc.com🌐 limitlessbsc.com