What is a double-storey extension?

A double-storey extension (also called a two-storey extension) adds rooms on both the ground and first floor in one build. It typically gives a larger kitchen or living space downstairs and an extra bedroom or bathroom above.
How much does a double-storey extension cost in Faversham?
In Faversham, a double-storey extension typically costs £1,850–£2,800 per m² of floor area (both floors), including VAT at 20% (standard rate). For a typical 36 m² project that is roughly £66,500–£101,000. Prices across the South East are typically 12% above the UK average for this kind of work, which is reflected in the range for Faversham. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (25 m²) | £46,000–£70,000 |
| Typical project (36 m²) | £66,500–£101,000 |
| Larger project (50 m²) | £92,500–£140,000 |
| Rate per m² | £1,850–£2,800 |
What moves the price most:
- Brick matching and external finishes
- Steel beams where walls are opened up
- Scaffolding and access to the rear
- Total floor area across both floors
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 double-storey extension in Faversham?
Here is how the rules work for a double-storey extension in England. In England an extension of more than one storey can only be permitted development at the rear, no more than 3 metres deep and at least 7 metres from the rear boundary, with matching materials and any upper side windows obscure-glazed. Most double-storey extensions therefore go through a householder planning application.
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.
At the survey we check your house’s planning history and any restrictions, and tell you which route applies.
What we handle
What we take care of:
- Structural engineer’s calculations
- Windows, doors and staircase alterations
- Brick or block walls, floors and a roof tied into the house
- Design drawings and planning application
- Foundations, drainage and scaffolding
- Electrics, heating, plumbing and plastering
How long does it take?
Allow 14 to 20 weeks on site, after planning and building control approval. Before that, surveys, drawings and approvals usually take 3 to 4 months, longer if the council asks for changes.
Building in Faversham
Commuter towns across the South East have many 1930s and post-war semis that suit rear extensions and hip-to-gable loft conversions.
We work across Faversham and neighbouring areas such as Whitstable, Sittingbourne and Canterbury. Postcodes we cover in Faversham include ME13.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Design and pricing
Design options, then a fixed quote based on the chosen drawings and specification.
- 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 double-storey extensions in Faversham
How much does a double-storey extension cost in Faversham?
In Faversham, a double-storey extension typically costs £1,850–£2,800 per m² of floor area (both floors), including VAT at 20% (standard rate). A typical 36 m² project comes to roughly £66,500–£101,000. Your fixed price depends on the survey and drawings.
What drawings do I need?
Planning drawings for the application, then more detailed building regulations drawings and structural calculations for building control. We prepare both.
Who approves a double-storey extension in Faversham?
Planning matters in Faversham go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
Can I live at home during the work?
Most families stay put. The shell is built first and the house is opened up late in the job, so disruption inside is limited to a few weeks.
Will the first floor need a new staircase?
Not normally. The new rooms are reached from the existing landing, though a doorway or short corridor may need to be formed.
