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 Hythe?
In Hythe, 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 Hythe. 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 |
The biggest cost drivers are:
- Total floor area across both floors
- Scaffolding and access to the rear
- Steel beams where walls are opened up
- Bathrooms or en-suites on the first floor
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 Hythe?
Before anything is built in Hythe, we confirm which approvals apply 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.
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.
We check this for your address before design work starts, so there are no surprises later.
What we handle
On a typical double-storey extension we handle:
- Design drawings and planning application
- Building control sign-off
- Structural engineer’s calculations
- Foundations, drainage and scaffolding
- Brick or block walls, floors and a roof tied into the house
- Opening up at both levels with steel beams
How long does it take?
Allow 14 to 20 weeks on site, after planning and building control approval. Design and approvals come first and typically take 3 to 4 months, depending on the approval route.
Building in Hythe
Commuter towns across the South East have many 1930s and post-war semis that suit rear extensions and hip-to-gable loft conversions.
Projects in Hythe (SO45) are surveyed in person before we quote, so the price reflects your actual property.
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
Build and handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions about double-storey extensions in Hythe
Who approves a double-storey extension in Hythe?
Planning matters in Hythe 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 double-storey extension cost in Hythe?
In Hythe, 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.
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.
Is a double-storey extension cheaper per square metre?
Usually yes. You pay for one set of foundations and one roof but get two floors of space, so the cost per square metre is often lower than a single-storey extension.