Annexe extensions in Grimsby: design, approvals and build
A annexe 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 £52,000 inc VAT
- PlanningUsually a householder application
- Build time16–24 weeks on site
- Postcode districtsDN31, DN32, DN33, DN34, DN35
Do I need planning permission in Grimsby?
In England an annexe that stays part of the household and connects to the house is assessed as an extension, but its size usually takes it beyond permitted development, so a householder application describing the ancillary use is the normal route.
The planning position for a specific Grimsby address depends on its history and any designations, which is why we check it at the first visit.
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).
Who an annexe extension suits
- Relatives who need support close by
- Homes with a large side or rear garden
- Multi-generational families
How much does an annexe extension cost in Grimsby?
For Grimsby we adjust our national guide rates by ×0.95, the factor we use for East Midlands. Figures include VAT; your written quote after the survey replaces them.
Typical rates in Grimsby: £1,900 to £3,610 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| Studio annexe 25 m² | £52,000 – £65,500 | £57,000 – £71,500 | £71,000 – £90,500 |
| One-bedroom annexe 35 m² | £66,500 – £83,500 | £79,500 – £100,000 | £99,500 – £126,500 |
| Larger annexe 45 m² | £85,500 – £107,000 | £102,500 – £128,500 | £128,000 – £162,500 |
For a figure based on your own dimensions, use our guide-price tool.
Working in Grimsby
We cover Grimsby and the postcode districts DN31, DN32, DN33, DN34, DN35, DN37. Neighbouring towns we cover include Cleethorpes (2 miles), Scunthorpe (24 miles), Lincoln (30 miles), Gainsborough (31 miles).
For homes towards East Riding of Yorkshire, Hull is around 16 miles away. 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.
How the project works
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
It starts with a visit to your house to measure, check access and talk through ideas and budget.
Design and approvals
Once the layout is agreed, we deal with the council: planning permission or written confirmation that none is needed, plus building control.
Fixed written price
The price is fixed in writing once the design is settled, with a clear programme and payment stages.
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 annexe extensions
How long does an annexe extension take to build in Grimsby?
On site, typically 16 to 24 weeks once approvals are in place. Before that, allow 10–16 weeks design and approvals.
Who do I contract with for an annexe 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.
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.
Will an annexe affect council tax?
It can. Some annexes are assessed separately for council tax, with discounts or exemptions in some cases when occupied by a relative. Check with the Valuation Office Agency (England and Wales), your local assessor (Scotland) or Land & Property Services (Northern Ireland).
How much does an annexe extension cost?
Our guide range is about £1,900 to £3,610 per m² including VAT. A one-bedroom annexe of about 35 m² is typically £79,500 to £100,000 at standard spec in Grimsby.
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.