Following a grant of planning permission, it may be necessary to make amendments to the proposals that were originally approved. A non-material amendment may be applied for to approve a minor change to the planning permission which does not breach any conditions originally placed on the consent.

There is no statutory definition for ‘non-material’ as it can vary on a case-by-case basis. In general, if the change will increase the size, change the appearance of a development or have a large impact on other considerations then it will not be considered non-material.

Read more about this non-material amendment applications.

‍

A roof window (or skylight) is fitted flush within the slope of a roof, while a dormer projects outward, creating additional headroom and floor space.  

Both can be installed under permitted development but must meet specific size and position limits to qualify.  

Also consider building regulations for a new dormer, find out more on Planning Portal  

‍

Significant changes to insulation and thermal elements would normally require building regulations approval. The extent to which this applies depends on the existing insulation and what it will be replaced with.

If the work is completed by a member of a competent persons scheme, then an application for approval will not be required.

Find out more about insulation and building regulations on our common projects.

‍

Whether raising the height of an external door requires planning permission depends on the location of the door, location of the property and how drastic the height change will be.

For smaller changes to the side and rear of the property, permitted development rights may apply, meaning no application or planning permission is required.

Where the height change will be substantial and have a significant impact on the building’s appearance, planning permission is likely to be required. Especially in cases where the door to be heightened is on the principal elevation of the property.

‍Principle elevation - The most visible or prominent side of a structure, typically facing a street or public area. While often considered the 'front' of the building, it may not always contain the main entrance.

In designated areas such as conservation areas, or on listed buildings you may require additional approvals such as listed building consent.

If you believe permitted development rights apply to a small change, you can apply for a lawful development certificate to ensure this is the case.

Building regulations

Building regulations approval will likely be required where the change impacts the structure of a building, this primarily occurs when an opening is widened. When altering walls you may want to consult a structural engineer.

Adding a storey on top of an extension will always require an application for planning permission.

If you want to add a storey on top of your house under permitted development rights, it must be on the principal part of the house.

If you want to add an additional storey on top of your house, it can be permitted development. It is only permitted development if it follows certain rules:

The current house

• Is not a building containing one or more flats, or a flat contained within such a building
• Was constructed between 1 July 1948 and 28 October 2018
• Has not already had additional storeys added to it
• Is not on Article 2(3) land 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.

How many storeys can you add?

• If the house is one storey then one storey can be added
• If the house is two or more storeys then two storeys can be added

Where can the storeys be added?

• The additional storeys must be added to the principal part of the house. The principal part of the house is the main part of the house excluding any front, side or rear extension of a lower height (regardless of these being part of the original house or subsequent additions).
• Engineering operations must only include works within the existing curtilage of the house to strengthen existing walls and foundations

How high can it be?

• The house cannot exceed 18 metres in total height
• Each storey cannot add more than 3.5 metres to the total height
• If the house is not detached the total height cannot be more than 3.5 metres higher than the next highest building that the house is attached to, adjoins, or is in the same row as.
• The additional storeys must have an internal floor-to-ceiling height of no more than 3 metres, and no greater than the internal height of any existing storey within the principal part of the house.

What materials can be used?

The materials used must be of a similar appearance to those used in the construction of the exterior of the current house

Where can windows be placed?

Windows must not be placed in any wall or roof slope forming a side elevation of the house.

Following completion of development:

• The house 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.

 If any of the limits set out above are exceeded then an application for planning permission will be required. If you are unsure, you should contact your local planning authority.

Find contact details for your local planning authority.