Grimsby house extensions
Every type of house extension in Grimsby, from single-storey kitchen extensions to two-storey additions, side returns and orangeries. We design, handle the approvals and build.
- Postcode districtsDN31, DN32, DN33, DN34, DN35, DN37
- Price regionEast Midlands (×0.95)
- Planning rulesEngland
- Site visitFree, no obligation
What works best for Grimsby houses?
The East Midlands has plenty of inter-war and post-war semis and detached houses with room to extend, alongside Victorian terraces in the towns.
The types we would usually look at first for a home in Grimsby are double-storey extensions, single-storey rear extensions and side extensions, depending on the garden and how the house is laid out.
Guide prices for Grimsby
We publish guide prices so you can budget before anyone visits. For Grimsby they are adjusted by ×0.95, the factor we use across East Midlands.
| Extension type | Example size | Standard spec (inc VAT) |
|---|---|---|
| Kitchen extensions | 20 m² | £39,500 – £50,500 |
| Extensions over a garage | 12 m² | £23,500 – £31,000 |
| Conservatory replacement extensions | 14 m² | £28,500 – £37,000 |
| Orangery extensions | 16 m² | £42,500 – £53,500 |
| Double-storey extensions | 32 m² | £54,500 – £71,500 |
| Wraparound extensions | 25 m² | £54,500 – £69,000 |
| Side return extensions | 11 m² | £25,000 – £31,500 |
Planning and building control 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.
In England a two-storey rear extension is permitted development only if it projects no more than 3 m from the original rear wall, sits at least 7 m from the rear boundary, matches the roof pitch and uses obscure, non-opening side windows upstairs. Most two-storey extensions therefore go through a householder planning application, which costs £548 from 1 April 2026 and normally takes about 8 weeks.
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.
Applications are decided by the local planning authority (your district, borough or unitary council).
Grimsby and surrounding towns
Postcode districts we cover around Grimsby include DN31, DN32, DN33, DN34, DN35, DN37. We also work in nearby Cleethorpes (2 miles), Scunthorpe (24 miles), Lincoln (30 miles), Gainsborough (31 miles), Skegness (34 miles). Just over the East Riding of Yorkshire border, Hull is about 16 miles away.
Choose an extension type
- Extension plans and drawings · from £1,100
- Side extensions · from £20,500
- Conservatory replacement extensions · from £19,000
- Single-storey rear extensions · from £19,500
- Extensions over a garage · from £22,500
- Double-storey extensions · from £36,000
- Timber frame extensions · from £19,500
- Home office extensions · from £15,000
- Utility and boot room extensions · from £13,000
- Planning permission for extensions · from £300
- Bedroom extensions · from £24,500
- Glass box extensions · from £28,500
- Pitched roof extensions · from £21,000
- Side return extensions · from £17,000
- Building regulations for extensions · from £850
- Bungalow extensions · from £24,500
- Porch extensions · from £3,800
- Annexe extensions · from £52,000
- Wraparound extensions · from £34,000
- Flat roof extensions · from £19,500
- Orangery extensions · from £28,500
- Kitchen extensions · from £25,500
Free site visit
A designer visits, takes measurements and photos, and discusses layouts, budget and timing with you.
Design and approvals
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
Fixed written price
With the design and specification agreed, you get a fixed written price and a start date.
Build and sign-off
Work is carried out to the agreed programme, inspected by building control and signed off at the end.
Questions about extensions in Grimsby
How much does an extension cost in Grimsby?
Using our East Midlands factor (×0.95), a standard-spec single-storey extension of 20 m² is a guide £38,500 to £49,500 including VAT, and a 32 m² two-storey extension £54,500 to £71,500. Your written price follows the survey.
Do I need planning permission for an extension in Grimsby?
Not always. It depends on the size, position and your property's history. Many single-storey rear extensions in England are permitted development or can use prior approval.
Can I get a price before anyone visits?
Yes. This page shows guide prices adjusted for Grimsby, and the guide-price tool gives a range for your own size and finish in about a minute.
Do you cover all of Grimsby?
Yes, including the surrounding parts of Lincolnshire. Site visits are free and there is no obligation.
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.