Two-storey extensions for detached houses in Freshwater
Our two-storey extensions for detached houses service in Freshwater covers everything: measured survey, design, planning or permitted development checks, structural design, building control and the build itself.
We take on projects in Freshwater by arrangement. Site visits here aren't free as standard, and we'll agree travel costs with you in writing first.
Before you start in Freshwater, here's what applies.
- Postcode districts
- PO39, PO40 and PO41
- County / area
- The Isle of Wight, England
- Price region
- South East England
- Guide price
- £94,500–£127,000 (£2,260–£3,030 per m²)
- Approval route
- Depends on position: a two-storey rear extension may be permitted development (3 m deep, 7 m from the rear boundary); a two-storey side extension needs planning permission.
- Nearest towns
- Newport (Isle of Wight) (10.4 miles), Cowes (11.4 miles), East Cowes (11.6 miles)
- Distance to Newport (Isle of Wight)
- about 10.4 miles
- First visit
- By arrangement
About a two-storey extension for a detached house
A two-storey extension for a detached house is a two-floor addition to the side, rear or both of a house that stands on its own plot. Detached houses often have room on more than one side, so there is more choice of layout and fewer shared-wall issues. The design still needs to respect boundaries, neighbours' windows and the look of the house.
Around Freshwater we also work in Newport (Isle of Wight), Cowes and East Cowes, and across the rest of the Isle of Wight. Postcode districts in and near Freshwater: PO39, PO40 and PO41.
What it costs in Freshwater
Expect a two-storey extension for a detached house in Freshwater to land somewhere around £94,500–£127,000 for a 3 m × 7 m footprint on two floors (42 m² of new floor space). Our South East England guide rate is £2,260–£3,030 per m², including VAT. Steelwork for wide openings is the item most likely to move the figure; we'll know once the engineer has designed it.
| Spec | Per m² | A 3 m × 7 m footprint on two floors (42 m² of new floor space) |
|---|---|---|
| Essential | £2,070–£2,780 per m² | £87,000–£117,000 |
| Standard | £2,260–£3,030 per m² | £94,500–£127,000 |
| Premium | £2,710–£3,630 per m² | £113,500–£152,500 |
Planning and building regulations in Freshwater
In England, a two-storey rear extension on a detached house can be permitted development within 3 m of the original rear wall and at least 7 m from the rear boundary, with matching roof pitch and materials, outside protected areas. Any two-storey side or wraparound extension needs planning permission, costing £548 (or £575 for applications made from 8 December 2026), with a decision due within 8 weeks of validation.
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 Freshwater homes
Keeping it subordinate
Large detached houses can take a large extension, but councils still expect it to look secondary to the main house. A lower ridge, a modest set-back at the front and matching materials keep the proportions right, even on a wide plot.
Larger spans and steelwork
Bigger extensions often mean wider openings and longer spans, which need more steel and sometimes a steel frame. The engineer designs these early, because the size of the steel affects ceiling heights, floor depths and the cost.
How we'd run your project
Visit by arrangement
We agree a visit to your home in Freshwater and any travel costs with you in writing first, then look at the structure, access and boundaries.
Design and approvals
We draw the extension and check it against the rules for England, then apply for planning permission or a certificate of lawfulness, whichever fits.
Engineer it
Foundations sized for two floors, steels for any openings, and building control approval, all before anyone starts on site.
Build
Foundations, walls, floor, roof, windows, then first and second fix. We break through into the house as late as we can.
Questions about two-storey extensions for detached houses in Freshwater
Who handles building regulations for a project in Freshwater?
We handle it as part of the project. What's needed in England: building regulations approval (full plans recommended) from the council or a registered building control approver, with a completion certificate at the end. We prepare the drawings and the engineer's calculations, book the inspections and pass you the completion paperwork at the end.
Which postcodes do you cover around Freshwater?
We cover Freshwater (PO39, PO40 and PO41) and nearby places including Newport (Isle of Wight), Cowes and East Cowes, plus the rest of the Isle of Wight. Visits and projects in Freshwater are by arrangement, with travel costs agreed in writing first.
How much does a two-storey extension for a detached house cost in Freshwater?
Our guide for South East England, which covers Freshwater, is £2,260–£3,030 per m² including VAT. A typical project with a 3 m × 7 m footprint on two floors (42 m² of new floor space) comes to about £94,500–£127,000. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.
How big an extension can a detached house take?
It depends on the plot, the boundaries and local design policy rather than a fixed limit. Under permitted development in England, extensions must not cover more than 50% of the land around the original house. With planning permission, the council judges size on proportion, neighbours and the character of the area.
Can I extend a detached house on both sides?
Sometimes. With planning permission, a council may accept extensions on both sides if the house stays well proportioned and keeps gaps to the boundaries. It is more common to extend on one side and the rear, or with a wraparound. We look at the plot as a whole before suggesting more than one extension.
Nearby
The same service in neighbouring towns:
Other extensions in Freshwater
- Rear
- Side
- Wraparound
- Part two-storey
- Over a garage
- First floor
- Semi-detached
- Kitchen and bedrooms
- Bedroom and en-suite
All two-storey extension services in Freshwater · Two-storey extensions for detached houses across the Isle of Wight
The quickest next step is a visit. We'll look at your house in Freshwater and give you an honest view of the options.