Permitted Development – Adding Additional Storeys to a House
Class AA - enlargement of a dwellinghouse by construction of additional storeys
Class AA of the General Permitted Development Order (GPDO) is another excellent planning tool. In this case, Class AA gives the ability to add additional storeys to an additional home.
Class AA of the GPDO will be particularly useful for homeowners who need extra space, but also property investors and developers, who are looking at ways to add value to a building through planning gain. Either way, Class AA can therefore be an excellent mechanism to generate property wealth and increase home equity without having to go through the normal planning processes.
There are of course some limitations and conditions that restrict where and when Class AA can be applied.
At the outset, it would be prudent to explore whether property is actually structurally strong enough to support additional storeys.
Please read on for a simple guide of the Class AA GPDO planning process. This could help you plan your next project.
How Many Storeys can be added under Class AA?
The GPDO allows up to two additional storeys, where the existing dwelling consists of two or more storeys; or one additional storey, where the existing dwelling is a bungalow.
Are there any situations where Class AA Does not Apply?
There are a number of scenarios where Class AA cannot be applied. These include:
Where the dwellings has originally been granted via another GPDO change of use e.g. via Class MA,
If the site is within a conservation area; an area of outstanding natural beauty; the Broads; a National Park; a World Heritage Site; an identified wildlife site; or a site of special scientific interest.
The dwelling was constructed before 1st July 1948 or after 28th October 2018. It may be necessary to have clear records of when the house was built, to prove it was built after 1948.
If the property has already been extended upwards.
Are there any height restrictions under Class AA?
The GPDO does place some height restrictions. These include:
Once complete, the highest part of the roof cannot exceed 18 metres in total.
The extensions cannot exceed the height of the original detached bungalow by more than 3.5m
The extensions cannot exceed the height of the original detached house by more than 7m
If the house is not detached, the height cannot exceed 3.5m of the highest part of the roof.
The floor to ceiling heights to be lower than 3m or lower than the existing floor to ceiling heights (whichever is lowest).
Any other restrictions under Class AA?
The additional storey can also only be on the principal part of the original house.
The support structures must not be on show on the exterior of the house.
Any engineering operations to strengthen the walls or existing foundations must be within the curtilage of the house.
Are there any Conditions that need to be met by Class AA?
There are a number of design conditions to meet. These include:
The materials used in any exterior work must be of a similar appearance to those used in the construction of the exterior of the existing dwelling.
The development must not include a window in any wall or roof slope forming a side elevation of the house.
The roof pitch must be at the same angle as the existing roof pitch.
No material impact on the amenity of any adjoining properties, including overlooking, privacy and the loss of light.
No material impact air traffic impacts
The Class AA Prior Approval Process
A Class Prior Approval planning application will need to be submitted to the local planning authority to judge whether the building complies with the requirements of the GPDO.
This Class AA Prior Approval application process for additional storeys to a home, costs £96 per dwelling.
The development must be completed within a period of 3 years starting with the date prior approval is granted;
Contact Us
Are you looking to extend your home of housing project? A D P can assist you by ensuring that you are compliant with Class AA, and we can prepare the necessary plans required for the Prior Approval application process. Please contact us mail@adpltd.co.uk or use the form below:
