Two-storey side extensions in Harwich
Adding a two-storey side extension in Harwich gives you two new rooms stacked on one footprint. Here's how we'd approach it, what it typically costs and the rules that apply in England.
The basics for Harwich at a glance.
- Postcode districts
- CO12
- County / area
- Essex, England
- Price region
- East of England
- Guide price
- £88,500–£119,000 (£2,110–£2,830 per m²)
- Approval route
- Planning permission is needed: in England, permitted development only allows single-storey extensions to the side.
- Nearest towns
- Felixstowe (3.2 miles), Walton-on-the-Naze (6.5 miles), Frinton-on-Sea (7.9 miles)
- Distance to Southend-on-Sea
- about 37.1 miles
- First visit
- Free, no obligation
About a two-storey side extension
A two-storey side extension is a new two-floor addition built into the space beside your house, often over a driveway or side passage. It typically adds one or two bedrooms upstairs and a utility, study or larger kitchen below, without giving up rear garden.
We cover postcode district CO12 in and around Harwich, along with neighbouring Felixstowe, Walton-on-the-Naze and Frinton-on-Sea.
What it costs in Harwich
A guide price for Harwich: around £88,500–£119,000 for a 3 m × 7 m footprint on two floors (42 m² of new floor space). That works out at £2,110–£2,830 per m² of new floor space, including VAT at 20%. Professional fees for drawings and the structural engineer are listed separately on our prices page.
| Spec | Per m² | A 3 m × 7 m footprint on two floors (42 m² of new floor space) |
|---|---|---|
| Essential | £1,940–£2,610 per m² | £81,500–£109,500 |
| Standard | £2,110–£2,830 per m² | £88,500–£119,000 |
| Premium | £2,530–£3,400 per m² | £106,500–£143,000 |
Planning and building regulations in Harwich
In England, a two-storey side extension always needs householder planning permission, because permitted development only allows single-storey extensions beyond a side wall. The fee is £548 (or £575 for applications made from 8 December 2026), and councils should decide within 8 weeks of validation. Expect them to look at set-back, roof height, gaps to the boundary and the effect on neighbours.
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 Harwich homes
Avoiding a terracing effect
Where semi-detached houses sit close together, side extensions on neighbouring houses can join up and turn a row of pairs into a terrace. Many councils ask for a gap to the boundary at first floor to stop this, so we check local guidance before fixing the width.
Access and services
Side extensions often cover the only route to the back garden, a gas meter, soil pipes or a drain run. We plan bin and bike access, move meters and pipes where needed and check drains early, because these items affect both cost and layout.
How we'd run your project
Visit and first ideas
One of our team visits your house in Harwich, checks the walls, roof and drains, and sketches out options with you.
Drawings and permission
Our designers produce plans and elevations, then we take care of planning or permitted development checks with the council covering Harwich.
Detail and price
Construction drawings, engineer's calculations and building control sign-off, then a written fixed price for the build.
Build and sign-off
Vetted teams working under S&K build the extension, and we arrange the building control completion certificate at the end.
Questions about two-storey side extensions in Harwich
Which postcodes do you cover around Harwich?
We cover Harwich (CO12) and nearby places including Felixstowe, Walton-on-the-Naze and Frinton-on-Sea, plus the rest of Essex. The first site visit is free.
Do I need planning permission for a two-storey side extension in Harwich?
Harwich is in England, so England planning rules apply. Planning permission is needed: in England, permitted development only allows single-storey extensions to the side. If in doubt, a lawful development certificate or a planning application gives you certainty before you build.
Who handles building regulations for a project in Harwich?
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.
How long does a two-storey side extension take?
Allow 4 to 8 weeks for survey and design, then the approval period (councils should decide householder applications within 8 weeks of validation), then 4 to 8 weeks of technical design, which can overlap. The build itself usually takes 14 to 20 weeks, longer for large or complex designs.
Can I build a two-storey side extension over my driveway?
Yes, if the drive is wide enough for a useful room and the council accepts the design. You may lose off-road parking, which some councils weigh up, and the foundations need to suit the ground below. We check parking, drains and meter positions at the free site visit before any drawings are prepared.
Nearby
Other towns near Harwich:
Other extensions in Harwich
- Rear
- Wraparound
- Part two-storey
- Over a garage
- First floor
- Semi-detached
- Detached
- Kitchen and bedrooms
- Bedroom and en-suite
All two-storey extension services in Harwich · Two-storey side extensions across Essex
The quickest next step is a visit. We'll look at your house in Harwich and give you an honest view of the options.