Hackney Extension Guide 2026: Planning Rules, Costs & Tips
Complete guide to extending your home in Hackney. New SPD guidance, planning permission requirements, conservation area rules, and typical costs.
TL;DR - The Quick Answer
Hackney has 29 conservation areas and Article 4 directions in Stoke Newington, Dalston, and De Beauvoir Town that remove standard permitted development rights. A new Residential Extensions SPD adopted in 2025 replaced the 2009 guidance and tightened design and sustainability requirements. Build costs run £2,000-2,900/m² for most extension types, rising 10-15% in conservation areas. Planning applications typically take 8-16 weeks depending on location and project complexity.
New Planning Guidance for Hackney (2025-2026)
Hackney adopted a new Residential Extensions and Alterations SPD in 2025, replacing the 2009 guidance. This updated policy provides clearer rules on extension design, sustainability requirements, and how to reflect Hackney's diverse local character. Mayfair Studio specialises in Hackney extensions from £1,295 - use our free AI chat to check your property's planning constraints instantly.
The borough has 29 conservation areas covering areas like Stoke Newington, Dalston, De Beauvoir Town, and parts of Hackney Central. Many of these areas have Article 4 directions that remove permitted development rights.
Permitted Development Rights in Hackney
Standard permitted development rules apply outside conservation areas and Article 4 direction zones:
| Extension Type | Max Without Permission | Hackney Notes |
|---|---|---|
| Single-storey rear (detached) | 4m deep, 4m high | Check for Article 4 directions first |
| Single-storey rear (semi/terrace) | 3m deep, 4m high | Very limited in conservation areas |
| Side extension | Half width of house | Planning required in most areas |
| Two-storey rear | 3m deep max | Almost always needs permission |
| Basement | N/A | Always requires planning permission |
Key Restrictions
- All 29 conservation areas have some planning restrictions
- Article 4 directions in Stoke Newington, Dalston, De Beauvoir remove permitted development rights
- Listed buildings always require listed building consent
Design Requirements Under New SPD
The 2025 Residential Extensions SPD emphasizes design quality, local character, and sustainability.
Key Design Principles
- Respect local character: Match materials, proportions, and details of surrounding properties
- Sustainability: Energy efficiency, sustainable materials, rainwater management
- Neighbor amenity: Minimize impact on light, privacy, and outlook
- Garden retention: Preserve outdoor amenity space and biodiversity
Extension Costs in Hackney
| Extension Type | Cost per m² | Typical Total |
|---|---|---|
| Single-storey rear (20m²) | £2,000-2,600 | £40,000-52,000 |
| Side return (12m²) | £2,500-3,400 | £30,000-41,000 |
| Two-storey rear (40m²) | £2,200-2,900 | £88,000-116,000 |
| Loft conversion (30m²) | £1,800-2,500 | £54,000-75,000 |
| Basement (40m²) | £2,900-3,900 | £116,000-156,000 |
Conservation area premium: Add 10-15% for matching materials and heritage details
| Extension Type | Cost per m² | Typical Total |
|---|---|---|
| Single-storey rear (20m²) | £2,000–£2,600 | £40,000–£52,000 |
| Side return (12m²) | £2,500–£3,400 | £30,000–£41,000 |
| Two-storey rear (40m²) | £2,200–£2,900 | £88,000–£116,000 |
| Loft conversion (30m²) | £1,800–£2,500 | £54,000–£75,000 |
| Basement (40m²) | £2,900–£3,900 | £116,000–£156,000 |
Source: Mayfair Studio project data • Data as of 2026
Additional Costs
- Architect fees: £4,000-11,000 (10-15% of build cost)
- Structural engineer: £1,500-3,500
- Planning application: £206 (householder) or £462 (full planning)
- Party wall: £1,500-3,000 per neighbor
- Building Control: £800-2,000
Hackney extensions require planning permission in most cases - over 60% of the borough has Article 4 directions removing permitted development rights. Typical costs run £2,000–£2,900/m² inc VAT, rising 10–15% in conservation areas. The 2025 Residential Extensions SPD tightened design and sustainability requirements. Allow 8–16 weeks for planning.
Frequently Asked Questions
What are the extension rules in Hackney, London?
Hackney has 29 conservation areas with Article 4 directions removing permitted development rights in Stoke Newington, Dalston, and De Beauvoir. Standard single-storey rear extensions need no planning permission if under 3m depth (terraced) or 4m (detached). Build costs run £2,000-2,600/m² (standard) or £2,600-3,200/m² in conservation areas. Planning takes 8 weeks for standard applications, 12-16 weeks for conservation area cases.
Do I need planning permission for an extension in Hackney?
It depends on your property's location. In Hackney's 29 conservation areas (including Stoke Newington, Dalston, De Beauvoir, and Victoria Park), most extensions require full planning permission. Outside conservation areas, single-storey rear extensions under 3m depth typically qualify as permitted development (no permission needed).
How much does an extension cost in Hackney?
Extension costs in Hackney: £2,000-2,600/m² for single-storey rear extensions, £2,200-2,900/m² for two-storey extensions, £2,500-3,400/m² for side returns, and £2,900-3,900/m² for basements. Conservation area projects add 10-15% for matching materials. Total costs range from £40k for small single-storey to £200k+ for basements.
What is Hackney's new residential extensions SPD?
Hackney adopted a new Residential Extensions and Alterations SPD in 2025, replacing the 2009 guidance. It provides updated rules on extension design, sustainability requirements, and how to reflect local character. The SPD supports policies in Hackney's Local Plan and applies to all residential extension applications from 2025 onwards.
How long does planning permission take in Hackney?
Standard planning applications take 8 weeks in Hackney. Conservation area and Article 4 direction areas may take 10-13 weeks due to additional consultation. Complex applications (basements, multiple storeys) can take 12-16 weeks. Pre-application advice costs £150-500 and is recommended for conservation area properties.