Extensions over a garage in Immingham
For an extension over a garage in Immingham, the first questions are always the same: how big, which approvals, and what it will cost. This page answers all three for Lincolnshire.
Quick reference for homeowners in Immingham.
- Postcode districts
- DN38, DN39, DN40, DN41 and LN7
- County / area
- Lincolnshire, England
- Price region
- East Midlands
- Guide price
- £31,000–£45,000 (£1,720–£2,500 per m²)
- Approval route
- Planning permission is needed: in England, permitted development only allows single-storey extensions to the side.
- Nearest towns
- Grimsby (6.7 miles), Cleethorpes (8.4 miles), Hedon (8.7 miles)
- Distance to Lincoln
- about 29.9 miles
- First visit
- Free, no obligation
About an extension over a garage
An extension over a garage is a new first-floor room built on top of an existing attached garage, usually a bedroom, en-suite or study. It uses a footprint you already have, so it adds floor space without taking any garden. The garage walls and foundations often need strengthening or replacing to carry the new floor.
We cover Immingham (DN38, DN39, DN40, DN41 and LN7) and the places around it, including Grimsby (6.7 miles), Cleethorpes (8.4 miles) and Hedon.
What it costs in Immingham
Our guide for the East Midlands is £1,720–£2,500 per m² including VAT. On a project with 3 m × 6 m of new first-floor space (18 m²), that puts an extension over a garage in Immingham at roughly £31,000–£45,000. Design fees, structural calculations and approval fees are separate and listed on our prices page.
| Spec | Per m² | 3 m × 6 m of new first-floor space (18 m²) |
|---|---|---|
| Essential | £1,580–£2,300 per m² | £28,500–£41,500 |
| Standard | £1,720–£2,500 per m² | £31,000–£45,000 |
| Premium | £2,060–£3,000 per m² | £37,000–£54,000 |
Planning and building regulations in Immingham
In England, most garages sit beside the house, so building over one makes a two-storey extension beyond a side wall, which always needs planning permission. If the garage is at the rear, the 3 m and 7 m rules for two-storey rear extensions apply, measured from the original house. A householder application costs £548 (or £575 for applications made from 8 December 2026).
Approval in England: Householder planning application: £548 (or £575 for applications made from 8 December 2026). Lawful development certificate: £274 (about £288 for applications from 8 December 2026). Councils should decide householder applications within 8 weeks of validation.
Building regulations: Building regulations approval (full plans recommended) from the council or a registered building control approver, with a completion certificate at the end.
Design points for Immingham homes
Floor levels and headroom
Garage floors are often lower than the house, and the new first floor may not line up with the existing landing. We set the floor level to avoid awkward steps upstairs, while keeping enough headroom in the garage below for a car or storage.
Checking the garage foundations
Garages are often built on shallow strip footings sized for a single-storey wall and a light roof. A trial hole shows their depth and condition, and the engineer decides whether they can carry two storeys or need underpinning or new foundations inside the garage.
How we'd run your project
Look at the house
We start in Immingham with a free visit: measurements, photos, a look at the loft and drains, and a frank chat about budget.
Drawings and permission
Our designers produce plans and elevations, then we take care of planning or permitted development checks with the council covering Immingham.
Detail and price
Construction drawings, engineer's calculations and building control sign-off, then a written fixed price for the build.
On site
One project lead runs the job, keeps you updated and arranges inspections at each stage until completion.
Questions about extensions over a garage in Immingham
Which postcodes do you cover around Immingham?
We cover Immingham (DN38, DN39, DN40, DN41 and LN7) and nearby places including Grimsby, Cleethorpes and Hedon, plus the rest of Lincolnshire. The first site visit is free.
How long does an extension over a garage take?
Allow 4 to 8 weeks for survey and design, then the approval period (councils should decide householder applications within 8 weeks of validation), then 4 to 8 weeks of technical design, which can overlap. The build itself usually takes 14 to 20 weeks, longer for large or complex designs.
Do I need planning permission for an extension over a garage in Immingham?
Immingham is in England, so England planning rules apply. Planning permission is needed: in England, permitted development only allows single-storey extensions to the side. If in doubt, a lawful development certificate or a planning application gives you certainty before you build.
Do I need to convert the garage as well?
No. You can keep the garage for parking or storage and build only the room above, as long as the floor between them and any door into the house meet fire separation rules. Converting the garage at the same time is often good value, because the walls and foundations may be upgraded anyway.
How do I get into a room over the garage?
Usually through a new opening off the existing landing or a bedroom, so the stairs stay where they are. If the floor levels do not match, a step or two may be needed inside the new room. Where a landing opening is not practical, a new stair from a converted garage is an option.
Nearby
Nearby towns we cover for extensions over a garage:
Other extensions in Immingham
- Rear
- Side
- Wraparound
- Part two-storey
- First floor
- Semi-detached
- Detached
- Kitchen and bedrooms
- Bedroom and en-suite
All two-storey extension services in Immingham · Extensions over a garage across Lincolnshire
Book a free site visit in Immingham and we'll tell you what's possible, what approvals you need and what the design stage would cost.