Covering Grimsby
We work in Grimsby (DN32, DN34) and the places around it, including Cleethorpes, Hull and Scunthorpe.
Homes in the East Midlands
Across the East Midlands you find everything from city terraces to modern estates and stone villages, so the right extension depends a lot on the street and the materials around it.
What is a garden annexe?
A garden annexe is a separate single-storey building in the grounds of a house with its own bedroom, bathroom and kitchenette, used by family members as part of the main household. Unlike a garden office, an annexe that people sleep in normally needs planning permission and full building regulations approval.
- Foundations and drainage connections
- Brick, block or timber-frame structure
- Accessible design options for older relatives
What is the guide price for a garden annexe in Grimsby?
Use these ranges to budget for garden annexes; the survey turns them into a fixed price for the agreed specification.
| Garden annexes | Guide price incl. VAT |
|---|---|
| Standard specification | £2,400 to £2,900 per m² |
| Good specification | £2,900 to £3,400 per m² |
| High specification | £3,400 to £3,900 per m² |
Planning and building rules in Grimsby
Projects in England go through two separate checks. Planning (or confirmation that the work is permitted development) comes from the district, borough or unitary council, and building regulations approval comes from the council’s building control team or a registered building control approver. Where work touches a shared wall or digs near a neighbour’s foundations, the Party Wall etc. Act 1996 applies.
A self-contained annexe used for sleeping and living normally needs planning permission in England. Permitted development for outbuildings does not cover living accommodation.
What can change the price or programme?
- A level threshold and wider doors make the annexe suitable for later life.
- Council tax treatment depends on who lives there; check with your council.
How does the project run?
- Send us the details. Give us a postcode, a rough idea of size and some photos, by phone, form or the guide price tool.
- Free site visit. We measure up, look at access, drains and the structure, and talk through options and budget.
- Price and paperwork. The design is priced line by line, and we submit the planning and building control applications.
- We build it. Work follows an agreed programme, with inspections at each stage and a final sign-off.
Garden annexes: common questions
Do I need planning permission for a garden annexe?
Usually yes, because people will sleep in it. Outbuilding permitted development does not cover living accommodation.
How much does a garden annexe cost?
Around £2,400 to £3,900 per square metre including VAT, depending on finish and services.
Do you work in Grimsby?
Yes. Grimsby is within our coverage for garden annexes, along with nearby Cleethorpes and Hull.
Other towns nearby
- Garden annexes in Cleethorpes
- Garden annexes in Hull
- Garden annexes in Scunthorpe
- Garden annexes in Beverley
Learn more about garden annexes, or see every project we cover in Grimsby.

