Extensions over a garage for homes in Grantham
A over-garage extension in Grantham 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 GranthamFrom £22,500 inc VAT
- PlanningHouseholder application needed
- Build time12–18 weeks on site
- Postcode districtsNG31, NG32
How much does an over-garage extension cost in Grantham?
Labour and material costs vary across the UK, so for Grantham we use our East Midlands factor (×0.95). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Grantham: £1,710 to £3,230 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| Over a single garage 12 m² | £22,500 – £28,000 | £23,500 – £31,000 | £30,500 – £39,000 |
| Over a large single garage 16 m² | £27,000 – £33,500 | £31,500 – £41,500 | £41,000 – £52,000 |
| Over a double garage 24 m² | £41,000 – £50,500 | £47,500 – £62,000 | £61,500 – £78,000 |
Want a range for your exact size? The guide-price tool takes about a minute.
Extensions in and around Grantham
Across NG31, NG32, we can visit, measure and advise. The same team covers Stamford (19 miles), Spalding (22 miles), Lincoln (22 miles), Boston (26 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.
When an over-garage extension makes sense
- Homes where the landing can connect to the new room
- Families needing a bedroom without losing garden
- Detached and link-detached houses with an attached garage
Planning and approvals in Grantham
In England any side extension over one storey, including a room built over a side garage, needs a householder planning application. The fee is £548 from 1 April 2026 and councils aim to decide within 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.
If the work involves a shared wall, building on the boundary, or digging foundations within 3 m (sometimes 6 m) of a neighbour's building, the Party Wall etc. Act 1996 applies and notice must be served before work starts: two months for work to a party wall, one month for new walls on the boundary and for excavations.
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).
Our process, step by step
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
We visit your Grantham home, measure up, talk through what you want and check the planning position.
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 over-garage extensions
Do you cover all of Grantham?
Yes. We cover Grantham and the surrounding parts of Lincolnshire. Site visits are free and there is no obligation.
Who do I contract with for an over-garage extension in Grantham?
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.
Do I need building regulations approval in Grantham?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Can I keep using the garage during the build?
Usually not for parking. The garage roof is removed and the space below is used for access and props for part of the build.
Does building over a garage need planning permission?
In England and the rest of the UK, adding a storey over a side garage almost always needs a planning application, because two-storey side extensions are outside permitted development.
Book a free site visit in Grantham
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.