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128 City Road, EC1V 2NX, London,UK
Barnet is one of North London’s most desirable family boroughs, with stunning Edwardian and Victorian properties that are perfect for house extensions. Whether you need a rear extension, side return, or wrap-around extension, expanding your home adds significant value and living space.
At Fixiz LTD, we specialise in house extensions across Barnet. This guide explains everything you need to know.
Why Extend Your Home in Barnet?
- High property values mean excellent ROI on extensions
- Many properties have development potential
- Growing families need more space
- Premium locations make moving expensive
- Extensions add 15-25% to property value
Planning Permission for House Extensions
Many extensions in Barnet fall under Permitted Development if you:
- Don’t exceed 3m (attached) or 4m (detached) for single storey rear
- Keep within height limits
- Don’t exceed 50% of garden coverage
- Stay within boundary setbacks
Conservation areas in Totteridge and Monken Hadley require planning permission.
Types of House Extensions in Barnet
Single Storey Rear Extension
Most popular for kitchen-diners. Costs from £40,000-£65,000.
Side Return Extension
Ideal for Victorian terraces. Costs from £30,000-£50,000.
Wrap-Around Extension
Combined rear and side. Costs from £55,000-£85,000.
Double Storey Extension
Maximum space addition. Costs from £70,000-£120,000.
Building Regulations Requirements
All extensions require Building Regulations approval covering:
- Structural calculations
- Foundation design
- Insulation and energy efficiency
- Electrical and plumbing
- Fire safety
Average Costs in Barnet 2026
| Extension Type | Price Range |
|---|---|
| Side Return | £30,000-£50,000 |
| Single Storey Rear (3m) | £40,000-£60,000 |
| Single Storey Rear (6m) | £55,000-£80,000 |
| Wrap-Around | £55,000-£85,000 |
| Double Storey | £70,000-£120,000 |
How Long Does an Extension Take?
- Side return: 8-10 weeks
- Single storey rear: 10-14 weeks
- Wrap-around: 12-16 weeks
- Double storey: 16-20 weeks
Why Choose Fixiz LTD?
- Local expertise in Barnet properties
- Full project management from design to completion
- All work guaranteed and insured
- Transparent pricing
- Free site survey and quotation
Frequently Asked Questions
Q: Do I need planning permission?
A: Many extensions fall under Permitted Development, but conservation areas require planning.
Q: How much value will an extension add?
A: Typically 15-25% of property value, potentially £100,000-£200,000+ in premium Barnet areas.
Get Your Free Quote
Ready to extend your Barnet home? Contact Fixiz LTD today for a free survey and quote.
Serving High Barnet, Finchley, Whetstone, Totteridge, Mill Hill, and all N2, N3, N11, N12, N20, EN4, EN5 postcodes.