What is a garage conversion?

A garage conversion turns an integral or attached garage into habitable space, such as a study, playroom, bedroom or utility. The garage door is replaced with a wall and window, the floor is raised and insulated, and the walls and roof are brought up to building regulations.
How much does a garage conversion cost in Portishead?
In Portishead, a garage conversion typically costs £18,500–£30,500 for a single integral garage, including VAT at 20% (standard rate). Prices in the South West sit near the national average for this kind of work, and the range for Portishead reflects that. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A single integral garage | £18,500–£30,500 |
| Higher specification | £30,500–£38,000 |
The main things that change the cost:
- Single or double garage
- Whether planning permission is needed
- Integral, attached or detached
- Heating and flooring
A guide range is only a starting point: the guide price tool gives an instant figure for your size, and a free survey turns it into a fixed quote.
Do you need planning permission for a garage conversion in Portishead?
Before anything is built in Portishead, we confirm which approvals apply in England. In England converting an integral or attached garage usually does not need planning permission, unless a condition on the house removed permitted development rights (common on estates built in recent decades) or the house is listed. Building regulations approval is always needed.
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
The work we manage on a garage conversion:
- Drawings and building control application
- Electrics, heating and plastering
- Wall and ceiling insulation
- Building control completion
- New wall and window to replace the garage door
- Foundation check under the garage door opening
How long does it take?
The build itself usually takes 3 to 6 weeks on site. Design and approvals come first and typically take 6 to 12 weeks, depending on the approval route.
Building in Portishead
In parts of the South West, protected landscapes and conservation areas shape what can be built, so materials and roof forms are chosen carefully.
From BS20 outwards, we take on projects throughout Portishead and the surrounding parts of Somerset.
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 in place
We handle planning, building control and neighbour notices before work starts.
- 04
Build and sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about garage conversions in Portishead
Do I need planning permission for a garage conversion?
Usually not if the work is internal and the house keeps its permitted development rights. Many newer houses have planning conditions that remove those rights, in which case an application is needed.
How long does a garage conversion take in Portishead?
Typically 3 to 6 weeks on site. Design and approvals beforehand usually take 6 to 12 weeks.
Can a detached garage be converted?
Yes, but using it as separate living accommodation may need planning permission.
Can the floor be level with the house?
Yes. The garage floor is raised and insulated to match the house floor level.
How much does a garage conversion cost in Portishead?
In Portishead, a garage conversion typically costs £18,500–£30,500 for a single integral garage, including VAT at 20% (standard rate). Your fixed price depends on the survey and drawings.
