Birmingham annexe extensions, designed and built
We design and build annexe extensions for houses in Birmingham, with a written price once the survey and design are done and one point of contact throughout.
- Guide price in BirminghamFrom £53,000 inc VAT
- PlanningUsually a householder application
- Build time16–24 weeks on site
- Postcode districtsB1, B2, B3, B4, B5
What is included
- Design for accessibility: level thresholds, wider doors, walk-in shower
- Kitchenette, shower room and bedroom finish
- Separate or shared heating and hot water
- Planning application describing ancillary use
- Fire separation and alarms to building regulations
Will the council need to approve it?
In England an annexe that stays part of the household and connects to the house is assessed as an extension, but its size usually takes it beyond permitted development, so a householder application describing the ancillary use is the normal route.
In a conservation area, national park, National Landscape, the Broads or a World Heritage Site the permitted development limits are tighter (no side or two-storey extensions without an application). Listed homes need listed building consent, and if permitted development rights have been removed, any extension needs an application.
Building regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.
If the work involves a shared wall, building on the boundary, or digging foundations within 3 m (sometimes 6 m) of a neighbour's building, the Party Wall etc. Act 1996 applies and notice must be served before work starts: two months for work to a party wall, one month for new walls on the boundary and for excavations.
Applications are decided by the local planning authority (your district, borough or unitary council).
How much does an annexe extension cost in Birmingham?
Labour and material costs vary across the UK, so for Birmingham we use our West Midlands factor (×0.97). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Birmingham: £1,940 to £3,690 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| Studio annexe 25 m² | £53,000 – £67,000 | £58,000 – £73,000 | £72,500 – £92,500 |
| One-bedroom annexe 35 m² | £67,500 – £85,000 | £81,000 – £102,000 | £101,500 – £129,500 |
| Larger annexe 45 m² | £87,000 – £109,500 | £104,500 – £131,000 | £130,500 – £166,000 |
For a figure based on your own dimensions, use our guide-price tool.
Working in Birmingham
Site visits are available across Birmingham (B1, B2, B3, B4, B5, B19). Neighbouring towns we cover include Smethwick (3 miles), West Bromwich (5 miles), Shirley (6 miles), Halesowen (7 miles).
For homes towards Worcestershire, Bromsgrove is around 12 miles away. The West Midlands has a large stock of 1930s and post-war semi-detached houses, which are well suited to rear, side and over-garage extensions, plus Victorian terraces in the older inner areas.
Our process, step by step
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
We visit your Birmingham home, measure up, talk through what you want and check the planning position.
Design and approvals
We produce the drawings and structural design, and manage the approvals so they are in place before work starts.
Fixed written price
With the design and specification agreed, you get a fixed written price and a start date.
Build and sign-off
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Questions people ask about annexe extensions
Do you cover all of Birmingham?
Yes. We cover Birmingham and the surrounding parts of West Midlands. Site visits are free and there is no obligation.
Do I need building regulations approval in Birmingham?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Will my neighbours in Birmingham be involved?
If a planning application or prior approval is needed, the council notifies neighbours. If the work is on or near a shared boundary, party wall notices may also be needed.
Can the annexe have its own front door?
Yes, many do, but it should still connect to the main house to stay clearly part of it.
Will an annexe affect council tax?
It can. Some annexes are assessed separately for council tax, with discounts or exemptions in some cases when occupied by a relative. Check with the Valuation Office Agency (England and Wales), your local assessor (Scotland) or Land & Property Services (Northern Ireland).
Book a free site visit in Birmingham
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.