Building a garage

Building a detached garage will not require Building Control Approval (but may require planning permission) if it meets the following conditions:

  • Less than 30m2 floor area
  • Constructed of non-combustible material or is at least 1 metre away from the boundary

Converting a garage into a room

Garage conversions always require Building Control approval.

Please contact Building Control for advice before beginning work.

There are several elements considered under the Building Regulations when converting a garage:


Where the existing structure is a single leaf of brickwork, an additional inner leaf may be required. A foundation must be provided to carry any additional brickwork, including the blocking up of the large garage door. The condition and suitability of the existing foundation/floor can be checked when the door infill area is excavated.

Wall Thickness

If the existing wall is single leaf construction with piers, it must be checked for suitability and free from defects. If satisfactory, the wall could be considered suitable (subject to weather resistance and insulation).

Structural support

Should you provide any new, or widen any existing openings, to provide doors or windows, lintels will need to be provided to take the weight of everything above.

Weather Resistance

A wall of single leaf construction must be treated to provide satisfactory resistance to the passage of moisture. A waterproofing compound applied on the internal face and incorporated into a floor membrane may be an effective way of achieving this. The provision of an inner leaf to create a cavity wall will require a cavity tray at the base of the wall.

Floors (new and existing) should also have a suitable damp proof membrane.


You are required to insulate the walls and roof to habitable standards. The rate at which heat is lost is called the ‘U’ value, and manufacturers of materials will be able to provide you with advice regarding ‘U’ values on their products.


Windows must incorporate open-able vents of an area equal to 1/20th of the floor area of the room, and trickle vents to provide background ventilation of 8000mm2. If the new room can only be accessed via another room, a suitably sized open-able window should be provided for means of escape purposes.


Please contact the Building Control team for a copy of the application form you require via email or by phone:

Non-domestic premises


For some Full Plans applications, part of the fee is payable upon submission of the application and the other part is invoiced for, after the first inspection by Building Control officers. This is dependent on the work category and is shown within the charges information.

For a Building Notice application, a fee is payable upon submission of the application.

Please contact Building Control regarding fees:

Please contact the Building Control Helpline and the Team will be able to provide you with a fee quote

  • 0161 770 4122