What is a side extension?
A side extension builds into the space beside a semi-detached or detached house, often over a driveway or side passage. It can be single-storey, for a utility room, downstairs toilet or study, or two-storey to add a bedroom above.
How much does a side extension cost in Peterborough?
In Peterborough, a side extension typically costs £1,800–£2,800 per m² of floor area, including VAT at 20% (standard rate). For a typical 28 m² project that is roughly £50,500–£78,500. The guide for Peterborough reflects typical costs in the East of England, roughly 6% above the UK-wide figure. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (20 m²) | £36,000–£56,000 |
| Typical project (28 m²) | £50,500–£78,500 |
| Larger project (39 m²) | £70,000–£109,000 |
| Rate per m² | £1,800–£2,800 |
The biggest cost drivers are:
- Boundary walls and access for materials
- Drains, gas meters or soil pipes that need moving
- Single or two storeys
- Roof design and tile matching
A guide range is only a starting point: the guide price tool gives an instant figure for your size, and a free survey turns it into a fixed quote.
Do you need planning permission for a side extension in Peterborough?
Approvals for a side extension in Peterborough follow the rules for England. In England a single-storey side extension can be permitted development if it is no more than 4 metres high and no wider than half the width of the original house. Side extensions of more than one storey always need planning permission, as do side extensions in conservation areas, National Parks and National Landscapes.
Building regulations approval comes from the council’s building control service or a registered building control approver. The work is inspected at key stages, such as foundations, drainage and insulation, and a completion certificate is issued at the end.
Our first visit includes a check of your planning history, so you know the route before paying for drawings.
What we handle
The work we manage on a side extension:
- Foundations and drainage alterations
- Opening into the existing house
- Structural calculations
- Electrics, heating and plastering
- Building control completion
- Walls, roof and windows to match the house
How long does it take?
The build itself usually takes 10 to 16 weeks on site depending on size and storeys. Design and approvals come first and typically take 3 to 4 months, depending on the approval route.
Building in Peterborough
Across the East of England, 1930s and post-war semis, newer estates and rural cottages all feature, each with different extension and loft options.
Peterborough sits in Cambridgeshire, about 30 miles north-west of Cambridge. We cover the whole of Peterborough, including postcodes PE1.
How it works
- 01
Survey and brief
We visit, discuss your ideas and budget, and survey the property or site at no cost.
- 02
Design and fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 03
Approvals
Planning or permitted development confirmation, building regulations and any party wall matters.
- 04
Build and sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about side extensions in Peterborough
How much does a side extension cost in Peterborough?
In Peterborough, a side extension typically costs £1,800–£2,800 per m² of floor area, including VAT at 20% (standard rate). A typical 28 m² project comes to roughly £50,500–£78,500. Your fixed price depends on the survey and drawings.
Can I build a side extension without planning permission?
In England a single-storey side extension can be permitted development if it is no more than 4 metres high and no wider than half the original house, and the house is not in a conservation area or similar protected land. Two-storey side extensions always need planning permission.
Will I lose my driveway?
A side extension often takes the side drive. We look at whether parking can be kept at the front and whether a dropped kerb is needed.
Will a two-storey side extension look odd?
Not if it is designed well. Setting it back from the front and keeping the roof lower than the main ridge usually gives a natural look and is what most councils ask for.
How long does a side extension take in Peterborough?
Typically 10 to 16 weeks on site depending on size and storeys. Design and approvals beforehand usually take 3 to 4 months.