Garage conversion plans in London

Do you need planning permission to convert a garage?

Frequently not. The law treats internal changes this way: Works affecting only the interior, or not materially affecting external appearance, are not development. If you keep the front looking like a garage, the project may need no application at all.

Where you replace the door with a wall, the exterior matters. The rule on materials is: Exterior materials must be of similar appearance to the existing house (conservatories excepted). That is why the choice of brick bond and colour is on our drawings from the start.

A previous planning condition can still block a conversion: some estates were approved on the basis that garages stay as parking. We check the planning history for exactly that during the free constraints check, and a Lawful Development Certificate can confirm the position in writing when it is clear.

When a householder application is the route

A householder application is needed where a condition removes the freedom, where the house is a flat, or where the conversion adds an extension. The council fee for altering a single dwellinghouse is £548 from the current fee table, paid to the council on top of our fixed fee.

Conservation areas and Article 4 directions can also restrict external changes to a front elevation. Our planning drawings set then carries the application, drawn to the council's design guidance.

We give the route before you pay: after the constraints check you know whether you are building under no application, with a certificate or with a householder permission.

Building Regulations for a converted garage

Even when planning is not needed, a garage conversion always needs Building Regulations approval, because a store becomes a habitable room. The heat-loss rules are the first test: New elements in existing dwellings, limiting U-values W/(m²·K): roof 0.15, wall 0.18, floor 0.18, windows 1.4 (or WER Band B), doors 1.4.

Safety comes next. For a bedroom the escape window rule says: Escape window: unobstructed openable area at least 0.33 m², at least 450 mm high and 450 mm wide, bottom of opening no more than 1100 mm above floor. Ventilation is in Approved Document F: Intermittent extract: kitchen 30 l/s with cooker hood (60 l/s otherwise), utility 30 l/s, bathroom 15 l/s, WC 6 l/s.

Alarms complete the picture: All dwellings: fire detection and alarm system minimum Grade D2 Category LD3 (BS 5839-6), mains-operated smoke alarms to BS EN 14604. These are drawn onto the technical set so building control can approve it first time.

Garage conversion plan prices

Garage conversion plans start at £695, VAT included. The price is published and fixed, and we confirm it after the free constraints check.

If a householder application is needed, the council fee is paid separately to the council. If the council asks for changes, we redraw at no charge until approval, which commits our fees and not the council's decision.

Planning a home office instead? A garden room may be simpler. Adding a self-contained unit is a larger project, covered under flat conversion drawings.

From survey to submission

We survey the garage and the neighbouring walls on one datum, including the floor level against the house and the drain runs. Then we model it in 3D and show you options for the front and the room layout.

You choose in writing and the design is frozen. A second chartered technologist, not the drawer, checks each sheet and a senior review signs it off.

Drawings are normally ready about a week after the survey. We then handle the certificate or application and any officer questions, with amendments inside five working days.

Things to settle before the drawings start

The first question is where the car goes. An original planning condition may require the garage to stay as a garage, and some councils expect parking to be kept. Read the decision notice for the house if you have it. If not, we find it in the planning history during our constraints check.

The second is the front. Replacing a garage door with a window and wall changes the street view, so we draw the new brickwork and window on the elevation and section drawings, matching bond and materials to the house.

The third is the floor and the walls. Old garage slabs are often thin and uninsulated, and the walls may be single skin, so the thermal and damp details need care. They go on your building regulations drawings, so a builder prices an insulated floor rather than guessing.

Garage conversion plans by council

Councils differ on front elevations, parking and conservation areas. Their pages give the local figures. Start with architectural drawings in Camden to see the kind of constraints that can apply.

Pick your borough from architectural drawings by area.