Need planning permission for a house extension or loft conversion?
Whether your house extension or loft conversion needs planning permission depends on your property and your aims. We assess Permitted Development, Prior Applications and Local Authority planning options to find the best route.
Do you need planning permission for a house extension or a loft conversion?
Different types of developments require different types of applications. Applications vary between house extensions, loft conversions, porches, outbuildings and garage conversions.
1. Permitted Development Applications (Lawful Development Certificates): national grants of permission by the General Permitted Development Order, which allow certain building works and changes of use to be carried out without requiring a planning application. Permitted Development Applications can be used for:
- Proposed developments or proposed change of use for a building or land
- An existing use or building (4 years and 10 years rule)
2. Prior applications:
- A larger home extension (6m or 8m single-storey rear extensions)
- Change of Use applications
3. Local Authority grants of planning permission:
- Householder Planning Application
- Full Plans Applications
Deciding which application type to use depends on many factors. For example:
- your needs and aims
- the site, the age and the type of property
- time limits
- budget
- practicality
Can you build the development as permitted development?
As Permitted Developments and Prior Applications are the easiest options, and sometimes the only possible options (for example a hip-to-gable loft conversion), we look into whether these are possible on your site. The following questions need to be answered during stage 1 of the application process, as some properties' rights are removed or restricted:
- Is the property a house (C3 use)? If it is a flat, maisonette or commercial you may not do it.
- Is the house a listed building? If so, listed building consent is required and very limited Permitted Development Rights are available.
- Is the house on Article 2(3) land (conservation area, AONB etc)? If so, there are very limited Permitted Development Rights available.
- Is there any Article 4 direction which removes Permitted Development Rights?
- Have the Permitted Development Rights been removed with restrictive covenants, conditions on the deed or a previous planning application (e.g. built after the 1960s)?
- Has the site been previously extended?
If your development complies with the permitted development rules we can make an application to get a Lawful Development Certificate, which will be requested by the solicitor when you are selling the house. Or, if you are very certain that your development complies with all the Permitted Development Rights, you may simply build, taking the risk.
Can you build the development with a Prior Application?
A prior application for a larger single-storey rear extension (6m or 8m) still requires a notification application completed before starting on site. We check if there is an Article 4 direction, which restricts how much you can extend your home. Your neighbours who share a boundary with your property will be consulted by the council. If they object, the council may refuse it. It is not possible to undertake this process retrospectively. If your neighbours raise concerns or objections, the local authority will determine whether the proposal's impact on the amenity of all adjoining properties is acceptable, and based on this, whether it can go ahead. The development must comply with other permitted development rules too.
Local Authority grants of planning application
After considering all these questions, if we find that a Prior Application or Permitted Development Application is not possible, practical or adequate, we look at the Local Authority grant of planning application option. If the property is a flat or maisonette, you will need a full Planning Application instead of a Householder Application.
Approval of this application is subject to the council's decision. We will discuss the possibility of approval, how to increase the chance of approval, and the issues at the first and second stage.
You cannot simultaneously build developments approved with different application types if they are connected. For example, you cannot build a permitted development loft conversion with dormer and at the same time a two-storey rear extension approved as a Householder Application. Some councils will include the approved permitted development in the Householder Application but some will insist on building them in different stages (e.g. Hillingdon Council). This can result in costly delays and should be checked at the beginning of the process.
How to increase the chance of approval of a planning application
When we are considering a Local Authority grant of planning application (householder or full plans), we consider the following issues and justify our proposed development to the planning department. We always prepare a Planning Statement or Design and Access Statement to address these before they are asked for by the officer:
- Is it in the Green Belt? Developments on Green Belt properties can be a maximum of 40-60% of the total enlargement of the original property. Openness will be an issue.
- Is it in a Flood Risk Area?
- Is it in a Conservation Area? If so, double-storey side extensions and front extensions are likely to be refused.
- Is it a listed building? If so, you will need a Listed Building Consent application too.
- Are there any Tree Preservation Orders?
- Size, type and age of the property? The extension should be proportional to the size of the main house and plot.
- Relationship to neighbouring buildings: right of light, any window on the side of the neighbour, their extensions, overlooking of neighbours' property.
- Is it in keeping with surrounding buildings? The new addition should match other buildings in material, size, scale and proportion.
- Terrace effect: if every house extends to the boundary, all houses in the street become terraced. A gap is required on the side between the extension and boundary depending on the street and council (1m or more for two-storey extensions).
- Is there a building line? If your proposal breaches an established building line along the road, the application can be refused.
- Is the extension subordinate to the main building? Extensions should keep the ridgeline lower than the existing ridgeline and recess the front of the extension.
- Is there any similar application approved nearby that we can use as an example to help our application?
- Parking: how many spaces are needed, and is it better to solve this before the application?
- Amenity space: will it be adequate after the extension?
- Can you make a combined application with a neighbour to overcome right-of-light issues?
- Is there any reason for the development, such as health issues, a disabled family member, or old-age requirements (e.g. a ground-floor bathroom and bedroom)?
- Are there any flat conversion or HMO applications on the street?
- How is the street for transport (PTAL rating), schools and shopping?
- Finally, council residential guidance, local policies and the London Plan should be checked to make sure your development is in line with their requirements.