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 Brierley Hill?
In Brierley Hill, a side extension typically costs £1,650–£2,550 per m² of floor area, including VAT at 20% (standard rate). For a typical 28 m² project that is roughly £46,000–£71,500. Prices in the West Midlands sit near the national average for this kind of work, and the range for Brierley Hill reflects that. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (20 m²) | £33,000–£51,000 |
| Typical project (28 m²) | £46,000–£71,500 |
| Larger project (39 m²) | £64,500–£99,500 |
| Rate per m² | £1,650–£2,550 |
Your quote will depend mainly on:
- Boundary walls and access for materials
- Single or two storeys
- Internal fit-out of the new rooms
- Roof design and tile matching
Use the guide price tool to see how size and specification change the figure, then ask for a written, itemised quote.
Do you need planning permission for a side extension in Brierley Hill?
Here is how the rules work for a side extension in 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.
If the answer is not clear-cut, we can apply for formal confirmation before you commit to the build.
What we handle
From survey to sign-off, the job normally involves:
- Walls, roof and windows to match the house
- Planning drawings and application
- Building control completion
- Opening into the existing house
- Foundations and drainage alterations
- Survey of the boundary, drains and access
How long does it take?
The build itself usually takes 10 to 16 weeks on site depending on size and storeys. Before that, surveys, drawings and approvals usually take 3 to 4 months, longer if the council asks for changes.
Building in Brierley Hill
The West Midlands has large numbers of 1930s semis and Victorian terraces, which suit rear extensions, side extensions and dormer loft conversions.
If your home is in Brierley Hill or close by in Stourbridge, Dudley and Kingswinford, 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
Drawings and written quote
We prepare the design and give you a written, itemised quote with inclusions and exclusions.
- 03
Approvals in place
We handle planning, building control and neighbour notices before work starts.
- 04
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about side extensions in Brierley Hill
Do you build side extensions in Brierley Hill?
Yes. We build side extensions across Brierley Hill, including postcodes DY5. Every project starts with a free home visit.
How much does a side extension cost in Brierley Hill?
In Brierley Hill, a side extension typically costs £1,650–£2,550 per m² of floor area, including VAT at 20% (standard rate). A typical 28 m² project comes to roughly £46,000–£71,500. Your fixed price depends on the survey and drawings.
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.
How long does it take?
Roughly 10 to 16 weeks on site once approvals are in place, depending on whether it is one or two storeys.
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.
