Planning & Formalities

Permission for extending a residential property is provided by the local authority in which the property resides. There are two different ways in which approval can be sought, these are Planning Permission and Permitted Development. The appropriate type of permission will depend on the type of development that you wish to carry out, and the type of property which you intend to carry out the works to. Below is a brief outline of the differences between the two types of permission:


Permitted Development is always the preferred option, as you are guaranteed approval if the scope of works and the property meet the criteria. All houses in the UK (not flats) that are not located within a conservation area, and are not listed or otherwise restricted, have Permitted Development rights. These PD rights allow the owner to extend the property in certain ways without applying for Planning permission from the local authority. In simple terms, the following types of development are considered Permitted Development:


Loft conversions which add up to 40 cubic metres in volume. Ground floor extensions which are no more than 3 metres in depth and 4 metres in height.


Loft conversions which add up to 50 cubic metres in volume.
Ground floor extensions which are no more than 3 metres in depth and 4 metres in height.


Loft conversions which add up to 50 cubic metres in volume.
Ground floor extensions which are no more than 3 metres in depth and 4 metres in height.


In 2013 the Government introduced a temporary scheme know as Prior Approval, which doubled the depth that properties can be extended under Permitted Development. However, gaining approval under this scheme requires that none of your immediate neighbours object to the proposal when they are consulted. If one of your neighbours does object to the proposal, the council will determine the application using a similar criteria to Planning Permission.



Any type of extension that does not comply with the Permitted Development regulations will require full Planning Permission. An application must be made to the local authority for this type of development, and it will be their responsibility to determine whether approval is granted. There are numerous factors that must be considered when assessing a Planning Application, but the key considerations will be the local authority’s planning policy and the local planning precedent. Planning policy and precedent can vary significantly between different boroughs and each application is decided on its own merits. We will advise you on what we think is attainable, based on our experience within the local area but often the process is not black and white and we will have to work with the local authority to find the best solutions on your behalf.



Whenever you are cutting into a party wall or digging foundations within 3 metres of your neighbour’s property, you must serve a party wall notice upon them. The party wall notice will give your neighbour the opportunity to appoint a Party Wall Surveyor and have a formal Party Wall Award drawn up. A Party Wall Award will document the condition of your neighbour’s property before the works are carried out, and will act as a point of reference in the event that any damage is caused by the work. Your neighbour can consent to he notice, which would avoid the need for a formal award, but if an award is required you will be responsible for the costs to your and your neighbour’s surveyor. You must have signed a Consent Notice of a formal Party Wall Award in place before any works commence.



If you own a share of freehold or you are a leasehold owner, you will need to obtain a License to Alter before your can carry out any works to your property. The specific process for this will be dependent on the provisions in your lease agreement, and we therefore advise that you consult a solicitor on the matter as soon as possible. Generally speaking, freeholder consent cannot be unreasonably withheld, but the degree of complication will depend on the terms of the lease and the freeholder you are dealing with. Although you cannot obtain a License to Alter without plans and structural designs, you should investigate this matter before instructing us to prepare any plans, as you may find the process is going to be lengthy, costly and it may make sense to consider moving instead.



If you are carrying out excavation work within 3 metres of a public sewer then you will require a Thames Water Build Over Agreement. This involves submitting the plans to Thames Water so that they can check the proposed construction is not going to have any adverse effect on the drain. Plus Rooms will handle the application on your behalf, but you will be responsible for Thames Water’s fee if a Build Over Agreement is required. We will carry out a drainage survey at your property as part of your Pre Project Package and advise you on whether the existing drainage has any implications on the build. We will do this in advance of the work where access to the drains is available. If the drainage on your land only services your property, then no Build Over agreement will be required as the drains are considered to be private.