Do you need planning permission to convert a garage?

Nothing in this Order permits development contrary to any condition imposed by any planning permission granted or deemed to be granted under Part 3 or Part 13 of the Act otherwise than by this Order.

Three things to check

1. Conditions on the house's permission. A permission can carry a condition that removes permitted development rights, or one that requires the garage to stay available for parking. The Order cannot override either (article 3(4)). A condition about how the garage is used can be breached by using it as a room, even where all the building work is internal. You can apply to vary or remove a condition under section 73 of the Town and Country Planning Act 1990. How to read a planning history explains where to find the conditions.

2. The garage door. Filling in the opening changes the outside of the house, so it relies on Class A. The materials must look similar to the existing house (A.3(a)). On Article 2(3) land, which includes conservation areas, cladding the infill in render, timber, tiles or similar is not permitted (A.2(a)), so a brick infill to match a brick house is the permitted development route there. An Article 4 direction may have removed Class A rights altogether. Building forward of the garage is an extension, and Class A allows no enlargement beyond the principal elevation (A.1(e)).

3. Who will live in it. A room used as part of the house is not a change of use. Using a building that was a single house as two or more separate homes is a material change of use (section 55(3)(a)), and the Planning Portal says a garage converted into a separate house may need planning permission whatever work is involved.

Detached garages

A detached garage is a separate building. Using it for a purpose incidental to the enjoyment of the house, such as a gym, a workshop or storage, is not development (section 55(2)(d)). Using it as living accommodation raises different questions, covered in annexes. Alterations to its outside rely on Class E, not Class A.

Building Regulations

The Planning Portal says converting a garage, or part of one, into habitable space will normally need Building Regulations approval. The work it lists includes filling in the door opening, the floor, walls below ground level, ventilation, and the new doors and windows. Where part of the garage stays, its guidance on internal walls asks for fire-resisting separation between that part and the new room.

What this means for you

Get the planning history for the house and read every condition before anything else. Then run the door infill through the permitted development checker. If a new dropped kerb or parking space is part of the plan, see dropped kerbs and driveways.

Getting certainty

A lawful development certificate under section 192 of the Town and Country Planning Act 1990 confirms that the conversion and the new front wall would be lawful, conditions included. From 1 April 2026 the fee for householder works is £274, and the council has 8 weeks to decide. Where a condition stands in the way, the route is a section 73 application or a householder application instead.