Single-storey rear extensions in Grimsby: design, approvals and build
A single-storey extension in Grimsby starts with the right design and the right approval route. We take care of both, then build it with our own project management.
- Guide price in GrimsbyFrom £19,500 inc VAT
- PlanningOften permitted development (3–4 m), or prior approval up to 6–8 m
- Build time10–16 weeks on site
- Postcode districtsDN31, DN32, DN33, DN34, DN35
What should I budget for a single-storey extension in Grimsby?
Labour and material costs vary across the UK, so for Grimsby we use our East Midlands factor (×0.95). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Grimsby: £1,660 to £3,230 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m 12 m² | £19,500 – £23,500 | £23,000 – £30,000 | £29,500 – £39,000 |
| 4 m × 5 m 20 m² | £33,000 – £39,000 | £38,500 – £49,500 | £49,000 – £65,000 |
| 5 m × 6 m 30 m² | £49,500 – £58,500 | £58,000 – £74,500 | £74,000 – £97,000 |
For a figure based on your own dimensions, use our guide-price tool.
Local to Grimsby
Postcode districts we cover around Grimsby include DN31, DN32, DN33, DN34, DN35, DN37. The same team covers Cleethorpes (2 miles), Scunthorpe (24 miles), Lincoln (30 miles), Gainsborough (31 miles), all within easy reach.
Homes across the East Midlands often have usable side land or a driveway beside the house, which opens up side and wraparound options.
Who a single-storey extension suits
- Terraced houses that want a deeper kitchen across the full width
- Semi-detached and detached houses with a usable rear garden
- Homeowners who want open-plan living onto the garden
Depth is the big decision. Every extra metre adds floor area but also takes garden and can push you out of permitted development. We draw the room at two or three depths so you can see the trade-off in space, light and cost before anything is fixed.
Do I need planning permission in Grimsby?
In England a single-storey rear extension can usually go up to 3 m beyond the original rear wall of a semi-detached or terraced house, or 4 m on a detached house, without a planning application, provided it is no more than 4 m high, keeps eaves to 3 m within 2 m of a boundary and, with other buildings, covers no more than half the land around the original house. The larger home extension prior approval scheme raises those depths to 6 m and 8 m, with neighbours notified and a 42-day decision.
Homes in conservation areas, national parks, National Landscapes (formerly AONBs), the Broads and World Heritage Sites have tighter rules, so we always check the property's status and planning history before design starts.
Building over or within 3 m of a public sewer needs the water company's consent, usually through a build-over agreement, before the foundations go in.
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
First, a site visit: we look at the house, garden, access and drains and listen to what you need.
Design and approvals
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
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
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Questions people ask about single-storey extensions
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Grimsby, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Do you cover all of Grimsby?
Yes. We cover Grimsby and the surrounding parts of Lincolnshire. Site visits are free and there is no obligation.
Who do I contract with for a single-storey extension in Grimsby?
Your contract is with S&K Property Investments and Improvement Ltd, which designs and manages the project and the build teams who carry it out.
How much does a single-storey extension cost per square metre?
Our guide range is about £1,660 to £3,230 per m² including VAT, depending on specification. A standard-spec 4 m × 5 m room usually lands at £38,500 to £49,500 in Grimsby, plus design and council fees.
How deep can a single-storey rear extension be without planning permission?
In England, up to 3 m beyond the original rear wall on a semi-detached or terraced house and 4 m on a detached house, within height and boundary limits. Through the larger home extension prior approval scheme those depths rise to 6 m and 8 m. Wales, Scotland and Northern Ireland use their own rules, which we check for your address.
Book a free site visit in Grimsby
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.