Extension cost in Birmingham (2026): local prices by postcode
Quick answerA 20m² single storey rear extension in Birmingham typically costs £54,500 to £62,500 including VAT. Birmingham prices change a lot by postcode: Edgbaston, Harborne and Moseley sit well above the city average, while Aston, Small Heath and parts of north and east Birmingham sit below it.
Typical prices in Birmingham
Kings Heath B14, West Midlandsindex 1.01- Single storey rear extension20 m² (5m × 4m)£54,500 to £62,500£2,900/m²
- Kitchen extension with bifolds24 m² (6m × 4m), mid spec£72,500 to £83,000£3,210/m²
- Double storey rear extension40 m² over two floors£87,500 to £100,500£2,330/m²
- Dormer loft conversion2 bedrooms + en-suite£49,000 to £57,500
- Velux loft conversion2 rooms£35,000 to £41,000
- Garage conversion15 m² single garage£20,000 to £23,000£1,420/m²
All prices include 20% VAT, professional fees and statutory planning fees. Kitchen extension includes a mid-range kitchen, bifolds and a roof lantern.
Price my exact projectBuilding in Birmingham
Birmingham is the largest extension market in the West Midlands, and one of the most varied. Moseley, Kings Heath and Selly Oak have long streets of Victorian and Edwardian terraces where side return and rear kitchen extensions are common. Harborne, Edgbaston and Hall Green have larger semis and detached houses suited to double storey and wraparound extensions. Bournville has its own character and controls, and the outer suburbs such as Northfield and Erdington have many interwar semis ideal for side extensions and loft conversions.
What moves the price in Birmingham
Postcode premiums
Builders in Birmingham price to the local market. Edgbaston, Harborne and Moseley attract higher quotes than Aston, Nechells or Kingstanding for the same work, because projects are larger, finishes are higher and demand is strong. We price each B district separately.
Terraced side returns
In Moseley, Kings Heath and Bearwood-style terraces, the side return is narrow and access is through the house. Steelwork to open up the rear wall, party wall agreements and drainage diversions are often needed, which adds cost per square metre.
Bournville and conservation areas
Bournville is managed by the Bournville Village Trust, and many homeowners there need the Trust's consent as well as council approval. Moseley, Edgbaston and other conservation areas also expect sympathetic designs and materials.
Planning in Birmingham
Planning and building control here are handled by Birmingham City Council. Many single storey rear extensions and loft conversions in England fall under permitted development, but conservation areas and Article 4 directions remove some of those rights, so check with the council before you commit to drawings.
Prices by postcode district in Birmingham
A 20m² single storey rear extension and a two-bedroom dormer loft with an en-suite, priced for each district. All figures include VAT and fees.
| Postcode | Area | Single storey, 20m² | Dormer loft | Index |
|---|---|---|---|---|
| B13 | Moseley | £56,000 to £64,500 | £50,500 to £59,000 | 1.04 |
| B14 | Kings Heath | £54,500 to £62,500 | £49,000 to £57,500 | 1.01 |
| B15 | Edgbaston | £57,000 to £65,500 | £51,500 to £60,000 | 1.06 |
| B17 | Harborne | £56,500 to £65,000 | £51,000 to £59,500 | 1.05 |
| B23 | Erdington | £52,500 to £60,000 | £47,000 to £55,000 | 0.97 |
| B28 | Hall Green | £54,000 to £62,000 | £48,500 to £56,500 | 1.00 |
| B29 | Selly Oak | £54,000 to £62,000 | £48,500 to £56,500 | 1.00 |
| B30 | Bournville | £55,000 to £63,000 | £49,500 to £58,000 | 1.02 |
| B31 | Northfield | £53,000 to £60,500 | £47,500 to £55,500 | 0.98 |
Birmingham: common questions
How much does an extension cost in Birmingham?
A 20m² single storey rear extension in Birmingham typically costs £54,500 to £62,500 including VAT, about £2,900 per square metre. A 24m² kitchen extension with bifolds and a lantern at mid spec is around £72,500 to £83,000.
Do I need planning permission for an extension in Birmingham?
Often not for a modest single storey rear extension, which can usually be built as permitted development. Conservation areas such as Moseley and Edgbaston, and estates with covenants such as Bournville, add extra checks. Confirm with Birmingham City Council before you start.
How much is a loft conversion in Birmingham?
A dormer loft conversion with two bedrooms and an en-suite typically costs £49,000 to £57,500 including VAT in Birmingham. Hip to gable conversions are common on the city's 1930s semis and cost a little more.
Which Birmingham postcodes are cheapest to extend in?
Generally Aston, Nechells, Small Heath, Saltley, Castle Vale and Kingstanding, where builders' prices sit below the city average. Your exact postcode gives a more accurate figure than the city as a whole.