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 Hartlepool?
In Hartlepool, a side extension typically costs £1,550–£2,400 per m² of floor area, including VAT at 20% (standard rate). For a typical 28 m² project that is roughly £43,500–£67,000. Building costs in the North East run about 10% below the UK average, and the figures for Hartlepool are adjusted to reflect that. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (20 m²) | £31,000–£48,000 |
| Typical project (28 m²) | £43,500–£67,000 |
| Larger project (39 m²) | £60,500–£93,500 |
| Rate per m² | £1,550–£2,400 |
Your quote will depend mainly on:
- Single or two storeys
- Internal fit-out of the new rooms
- Roof design and tile matching
- Steel work where the side wall is opened
For a figure based on your own measurements, try the guide price tool, then book a free home visit for a fixed quote.
Do you need planning permission for a side extension in Hartlepool?
Approvals for a side extension in Hartlepool 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
What we take care of:
- Electrics, heating and plastering
- Planning drawings and application
- Building control completion
- Foundations and drainage alterations
- Opening into the existing house
- 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. Allow time beforehand for drawings and approvals, usually 3 to 4 months.
Building in Hartlepool
Across the North East, colliery-era terraces and newer estates sit side by side, so the right project depends on the house type.
If your home is in Hartlepool or close by in Peterlee, Billingham and Middlesbrough, a free home visit is the first step.
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 pricing
Design options, then a fixed quote based on the chosen drawings and 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 Hartlepool
How close to the boundary can I build?
You can build up to the boundary, but the eaves height near it is limited under permitted development, and planning officers often want a gap at first floor. If you build on or near a shared boundary, party wall rules may apply.
Who approves a side extension in Hartlepool?
Planning matters in Hartlepool go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
How much does a side extension cost in Hartlepool?
In Hartlepool, a side extension typically costs £1,550–£2,400 per m² of floor area, including VAT at 20% (standard rate). A typical 28 m² project comes to roughly £43,500–£67,000. Your fixed price depends on the survey and drawings.
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.
Can a side extension go over a drain?
Often yes, with a build-over agreement from the water company or by rerouting the drain. We check this during the survey.
