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 North Yorkshire?
In North Yorkshire, a side extension typically costs £1,600–£2,450 per m² of floor area, including VAT at 20% (standard rate). For a typical 28 m² project that is roughly £45,000–£68,500. We start from a UK-wide guide and adjust it for Yorkshire and the Humber, where labour and materials are typically about 7% below average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (20 m²) | £32,000–£49,000 |
| Typical project (28 m²) | £45,000–£68,500 |
| Larger project (39 m²) | £62,500–£95,500 |
| Rate per m² | £1,600–£2,450 |
The main things that change the cost:
- Drains, gas meters or soil pipes that need moving
- Internal fit-out of the new rooms
- Boundary walls and access for materials
- Roof design and tile matching
Your exact price depends on the survey and drawings. The guide price tool gives a quick range in the meantime.
Do you need planning permission for a side extension in North Yorkshire?
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.
Where work involves a shared wall, building on the boundary, or digging foundations within 3 metres of a neighbour’s building and deeper than its foundations (or within 6 metres for deeper work), the Party Wall etc. Act 1996 applies and notices must be served before work starts.
We check this for your address before design work starts, so there are no surprises later.
What we handle
On a typical side extension we handle:
- Planning drawings and application
- Survey of the boundary, drains and access
- Foundations and drainage alterations
- Building control completion
- Electrics, heating and plastering
- Structural calculations
How long does it take?
Build time is typically 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 North Yorkshire
In Yorkshire, through-terraces and back-to-backs have particular constraints, while semis and detached houses suit larger extensions.
Towns we cover in North Yorkshire include York, Middlesbrough, Harrogate, Scarborough, Redcar and Selby.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 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
Build and handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions about side extensions in North Yorkshire
How much does a side extension cost in North Yorkshire?
In North Yorkshire, a side extension typically costs £1,600–£2,450 per m² of floor area, including VAT at 20% (standard rate). A typical 28 m² project comes to roughly £45,000–£68,500. 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.
Do you build side extensions in North Yorkshire?
Yes. We build side extensions across North Yorkshire, including postcodes BD20, BD22, BD23, BD24 and DL10. Every project starts with a free home visit.
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.
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.