Garage Conversion: A Beginner’s Guide - Detailed Planning

Garage Conversion: A Beginner’s Guide

10th March 2018

A garage conversion can add value to your property as well as additional living space to your home. Our Garage Conversion Guide takes you through what could be the ideal solution: a useful, additional space that is versatile, and convenient to both entranceways and the main living areas of your house.

Want to introduce an entirely independent new ‘wing’ to your home? Why not consider a garage conversion with its own, exclusive entrance, for purposes such as a home office, gym, or simply for an extra room.

A well-thought-out garage conversion can add as much as 10% to the value of your home. Expect to pay between £5,000 and £8,000 for converting the average single garage, making it one of the most cost-effective ways to improve your property’s resale value.  An additional benefit is increased living space without incurring the costs and inconveniences of moving house.

Planning Permission

Planning permission is unnecessary if you don’t plan to alter the structure of the building, so a garage conversion is permitted in most circumstances.

  • Standalone garages are more likely to require ‘change of use’ planning permission when converted to habitable rooms.
  • If you live in a Listed building or a Conservation Area, planning permission may be required for even minor modifications.

You can find out more about planning applications and decisions here.

Building Regulations

The change of use from a garage to a habitable room will mean compliance with Building Regulations, including delivery of a building notice to your council. Building Regulations apply to:

  • moisture proofing
  • ventilation
  • insulation
  • fireproofing
  • escape routes
  • structural soundness.

As a result, almost any design decision must take them into account.


Making garage conversions look like a natural part of your home, and less like a converted garage is vital to its success and your home’s future saleability. Before work starts, commission scaled drawings of the finished project, indoors and out, and include details such as power sockets and furniture layout.

Can you convert a garage yourself?

You can do most of the conversion yourself, which is ideal if you’re on a tight budget, but your work will be regularly inspected by building control officers and anything that’s not up to scratch will have to be undone at your own expense.

Get written quotes (not estimates) from three different companies, with a clear specification of what’s included. Using an architect can give a more creative result.


Design Control: Converting a garage means every step of the design process is under your control, subject to technical and legal restrictions.

Added Value: Moving house costs money that can’t be recouped. But converting a garage into a habitable room adds more value to your home than it costs in most cases.

Cost Effective Way to Add Space: Conversion costs for the average garage are between £5,000 and £8,000.


Disruption: During garage conversion, one or more existing rooms will frequently be rendered unusable by building work. Rooms adjoining the garage, and garden or yard space will be most affected.

Control of Work: The householder will be held responsible for the legality of work done on their property. Time and energy will be required supervising work, being present to allow tradespeople access and making design and other decisions.

Impact on Existing Buildings: Extending the garage will consume garden space. Light to existing rooms, access to the property, yard space and the exterior appearance of the building as a whole may all be affected.

Planning Uncertainty: Projects that require planning permission may not receive it. Application will involve a non-returnable fee, usually of about £150. This will be higher if you want to alter a listed building or you live in a conservation area.

Cost Uncertainty: Once investigations begin on your property, you might be required to pay for additional improvements or repairs.

For more information on garage conversions, check out Home Building’s Advice.

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