Annexe extensions across West Midlands
A annexe extension in West Midlands starts with the right design and the right approval route. We take care of both, then build it with our own project management.
- Guide priceFrom £53,000 inc VAT
- PlanningUsually a householder application
- Towns covered20
- Site visitFree, no obligation

Towns in West Midlands
Is an annexe extension right for your house?
- Multi-generational families
- Relatives who need support close by
- Homes with a large side or rear garden
Accessibility is cheaper to design in than to retrofit. Level access, a 900 mm door width, a level-access shower and space to turn a wheelchair can all be planned into the footprint for little extra cost.
Extensions in and around West Midlands
Towns we cover in West Midlands include Birmingham, Coventry, Wolverhampton, Dudley, Walsall, Solihull, Sutton Coldfield, West Bromwich. Across the West Midlands, brick-built semis with long gardens are common, so single-storey and two-storey rear extensions are popular choices.
Annexe extension prices in West Midlands
Prices below are for West Midlands, using the West Midlands factor of ×0.97. They are guide ranges including VAT for the build only, not a quote.
Typical rates in West Midlands: £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 |
Try the guide-price tool to see a range for your own size and finish.
Planning rules that apply in West Midlands
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.
The planning position for a specific West Midlands address depends on its history and any designations, which is why we check it at the first visit.
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.
Applications are decided by the local planning authority (your district, borough or unitary council).
What happens next
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
A designer visits, takes measurements and photos, and discusses layouts, budget and timing with you.
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
We confirm the build price in writing, based on the approved drawings and the finishes you have chosen.
Build and sign-off
Work is carried out to the agreed programme, inspected by building control and signed off at the end.
Common questions in West Midlands
Do I need building regulations approval in West Midlands?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Will my neighbours in West Midlands 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 I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for West Midlands, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
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.
Does an annexe extension need planning permission?
Usually yes, because of its size and the way it will be used. Councils check that it stays ancillary to the main house, so the application must describe the use clearly.
Book a free site visit in West Midlands
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.