House extensions in Portsmouth
Looking to extend your home in Portsmouth? Start here: extension types, guide prices for Portsmouth, the planning rules that apply and how a project runs.
- Postcode districtsPO1, PO2, PO3, PO4, PO5, PO12
- Price regionSouth East England (×1.12)
- Planning rulesEngland
- Site visitFree, no obligation
Areas we cover around Portsmouth
We cover Portsmouth and the postcode districts PO1, PO2, PO3, PO4, PO5, PO12. Neighbouring towns we cover include Gosport (2 miles), Fareham (5 miles), Havant (6 miles), Waterlooville (6 miles), Hythe (14 miles). Just over the Isle of Wight border, Ryde is about 6 miles away.
Guide prices for Portsmouth
We publish guide prices so you can budget before anyone visits. For Portsmouth they are adjusted by ×1.12, the factor we use across South East England.
| Extension type | Example size | Standard spec (inc VAT) |
|---|---|---|
| Single-storey rear extensions | 20 m² | £45,500 – £58,500 |
| Extensions over a garage | 12 m² | £28,000 – £36,500 |
| Wraparound extensions | 25 m² | £64,000 – £81,500 |
| Orangery extensions | 16 m² | £50,000 – £63,000 |
| Side return extensions | 11 m² | £29,500 – £37,000 |
| Kitchen extensions | 20 m² | £47,000 – £59,500 |
Planning and building control in Portsmouth
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 single-storey side return infill is often permitted development if it stays within the height limits and is no wider than half the width of the original house. Conservation areas, listed buildings and flats always need an application, and the boundary wall usually brings in the Party Wall Act.
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).
Which extension suits a Portsmouth home?
In the South East, plenty of houses have already been extended once, which makes checking the remaining permitted development allowance an important early step.
For many houses here, orangery extensions, single-storey rear extensions or wraparound extensions gives the most useful space for the budget.
Choose an extension type
- Utility and boot room extensions · from £15,500
- Annexe extensions · from £61,500
- Timber frame extensions · from £23,500
- Extension plans and drawings · from £1,300
- Flat roof extensions · from £23,500
- Glass box extensions · from £33,500
- Planning permission for extensions · from £350
- Kitchen extensions · from £30,000
- Pitched roof extensions · from £24,500
- Extensions over a garage · from £26,500
- Double-storey extensions · from £42,500
- Conservatory replacement extensions · from £22,000
- Wraparound extensions · from £40,000
- Porch extensions · from £4,450
- Single-storey rear extensions · from £23,500
- Orangery extensions · from £33,500
- Bedroom extensions · from £29,000
- Side return extensions · from £20,000
- Home office extensions · from £17,500
- Side extensions · from £24,500
- Bungalow extensions · from £29,000
- Building regulations for extensions · from £1,000
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
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
With the design and specification agreed, you get a fixed written price and a start date.
Build and sign-off
The build is managed from start to finish, inspected at each stage and signed off on completion.
Questions about extensions in Portsmouth
How much does an extension cost in Portsmouth?
Using our South East England factor (×1.12), a standard-spec single-storey extension of 20 m² is a guide £45,500 to £58,500 including VAT, and a 32 m² two-storey extension £64,500 to £84,500. Your written price follows the survey.
Do I need planning permission for an extension in Portsmouth?
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.
Will my neighbours need to be told?
If you apply for planning or prior approval the council notifies them, and in England party wall notices may be needed for work near a shared boundary.
How long does an extension take in Portsmouth?
Usually 2 to 4 months of design and approvals, then 10 to 16 weeks on site for a single-storey extension or 16 to 24 weeks for two storeys.
Book a free site visit in Portsmouth
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.