Cosham, Hampshire
Bungalow rear extension in Cosham
Thinking about a bungalow rear extension in Cosham? Single-storey rear extensions that keep everything on one level. Our team handles the drawings, the planning route and the build, and your contract is with one company throughout.
Cosham is covered from our Hampshire round, including PO2, PO3 and PO6. For bungalows in Hampshire, a rear extension is the usual way to add space without adding stairs.
Book a free site visit
Tell us about the house and we'll call to arrange a free, no-obligation visit.
How much does a bungalow rear extension cost in Cosham?
For Cosham we work from the South East England rate: £2,070–£3,360 per square metre of new floor, including VAT, standard specification. South East prices run above our West Midlands baseline, mainly on labour rates and clay-soil foundations.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £25,000–£40,500 |
| 4 m wide × 6 m deep (24 m²) | £49,500–£80,500 |
Ground conditions, glazing, the roof and how far the house is opened up move the final figure within the range.
Do you need planning permission for a bungalow rear extension in Cosham?
Here is how the rules in England apply to a bungalow rear extension in Cosham.
English permitted development (Class A) allows a single-storey rear extension of 3 metres on a terraced or semi-detached house and 4 metres on a detached one, measured from the original house, with a maximum height of 4 metres and eaves of no more than 3 metres within 2 metres of a boundary.
England also has the larger home extension route: a single-storey rear extension of up to 6 metres on an attached house or 8 metres on a detached house, after prior approval from the council. The council notifies your neighbours and has 42 days to decide; the fee is £249 (£310 for applications made from 8 December 2026). The route is not available on designated land such as conservation areas.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent. At the first visit we measure what is there now and tell you which route fits: permitted development, prior approval or a planning application.
What are homes in Cosham like to extend?
Commuter semis and detached houses make up much of Cosham, and longer gardens make England's prior approval route for deeper rear extensions worth considering.
How a bungalow rear extension in Cosham comes together
Survey visit
We visit free of charge, measure up, check access, drainage and neighbours' extensions, and note what you want the room to do.
Drawings and budget
Floor plans and elevations for the options, each with a guide price.
Approvals
Permitted development check, prior approval or planning application, then Building Regulations drawings and structural calculations, plus party wall notices where they apply.
Written price, then build
Once the design and approvals are in place, you get a fixed written price and programme, and we build through to sign-off.
Bungalow rear extensions near Cosham
Neighbouring places we cover include Waterlooville (2.8 miles) and Havant (3.5 miles).
- Bungalow rear extension in Waterlooville
- Bungalow rear extension in Havant
- Bungalow rear extension in Portsmouth
- Bungalow rear extension in Southsea
- Bungalow rear extension in Gosport
Other work in Cosham:
FAQ
Bungalow rear extension questions in Cosham
Is the site visit in Cosham free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.
How long does a rear extension take to build in Cosham?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.
Do I need to move out?
Rarely; the opening into the bungalow is made late in the build.
Do I need planning permission for a rear extension in Cosham?
Often not for a single-storey rear extension of up to 3 metres (4 metres on a detached house) under permitted development, or up to 6 or 8 metres with prior approval, unless the house is in a conservation area or its rights have been removed.
Do I need a party wall agreement?
In England, usually yes if the extension is on or near a shared boundary or the foundations are close to a neighbour's building. We serve the notices.
Do you handle building control in Cosham?
Yes. We apply to the council or a registered building control approver and hand over the completion certificate.