PLANNING RULES FOR EXTENDING UPWARDS BY ADDING STOREYS

EXTENDING UPWARDS BY ADDING STOREY – WITHOUT PLANNING PERMISSION

If you want to increase the available accommodation at your property or premises (or create new dwellings) by extending upwards, you may be surprised to hear that you may not need full planning permission to do so. 

Full planning applications cost money, take time, and require an assessment to be made by a local planning authority officer.  Your neighbours will be consulted and can object to your proposals. 

However, it is possible under planning rules in England to undertake certain works without the need to apply for planning permission – subject to ‘permitted development’ rules being met in terms of the size, type and location of the works.    

The relevant rules are set out in the Town and Country Planning (General Permitted Development) (England) Order 2015, as amended.   

The rules affecting the addition of storeys to existing buildings in England changed in 2020.

PRIOR APPROVAL

In place of a full planning application, a ‘fast-track’ submission is made to the LPA for what is known as ‘Prior Approval’.  So, whilst the principle of extending upwards is pre-established, your streamlined application will allow your local council to assess proposals only in relation to:

• the external appearance of the building/additional floors
• provision of natural light in habitable rooms
• any impact on the amenity of the existing residents and neighbours, including overlooking, privacy and the loss of light
• construction management – how noise, dust and other disruption will be managed

The local authority will notify and invite comments from owners and occupiers of the building being extended and adjoining premises before issuing their decision.

CONDITIONS

Householders proposing additional storeys must:

• Use materials which match the existing dwelling
• Not insert windows into any side elevation wall or roof slope

HOUSES – CONSTRUCTION OF UP TO TWO STOREYS

Building additional storeys on your house is ‘permitted development’ subject to ‘Prior Approval’ being issued and the following criteria:

The current house:

• Must be a single dwellinghouse and not a building containing any flats
• Constructed between July 1948 and March 2018
• Has not already had any additional storeys added to it
• Is not in a protected area (see below) or a site of special scientific interest
• Was not changed to be used as a house (from a previous non-residential use) under permitted development rights

Other limits and requirements:

• Just a single additional storey can be added to a bungalow
• Two storeys can be added to two (or more) storey houses
• The completed house cannot exceed 18m height (total)
• Each storey cannot exceed 3.5m
• If the house is in a terrace or is semi-detached, the total height of the completed dwelling cannot be more than 3.5m higher than the next highest building that house is attached to, adjoins or is in the same row as
• The additional storeys must be constructed on the principal part* of the house
• The additional storeys must not exceed three metres in height or the height of any existing storey in the principal part* of the house (measured internally from floor to ceiling)
• Engineering operations must only include works within the existing curtilage of the house to strengthen existing walls and foundations
• The original dwellinghouse must remain in use as a domestic residential property
• No visible support structures must remain on or attached to the exterior of the house
• The roof pitch of the principal part* of the house must be the same as it was prior to the development.

*Principal part of the house

Principal part of the house means the main part of the building excluding any front, side or rear extension of a lower height, whether this forms part of the original building or a subsequent addition.