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Do I need planning permission to build underground?
Creating a new basement will usually require planning permission, particularly if it affects the external appearance of the property. For example, installing a lightwell to bring natural light into the basement may be subject to stricter design rules if it is visible from the street, especially at the front of the property, compared to those at the rear or side.
Because basement construction involves significant excavation and structural work, permission is often necessary. It’s recommended that you consult your local planning authority early on to understand what is likely to be considered acceptable before submitting a planning application. Building regulations will also apply to a new or conversion of a basement.
Common Questions
Demolishing and building a new lean-to will still have comply with planning requirements.
If you live in a conservation area or listed building you may require approval for the demolition.
Whether a lean-to requires planning permission will depend on what the lean-to is used for, it may be an extension, pergola, carport, conservatory or gazebo.
In some cases a building a lean-to will be classified as permitted development, meaning an application for planning permission is not required provided specified limits and conditions are met. If these are exceeded, then you must apply for planning permission.
Permitted development rules vary based on the type of work you are completing, visit our interactive house mini guides for details on the specific rules.
If you live in a listed building, you will need listed building consent for any significant changes.
A carport can fall under permitted development rights provided it meets certain limits and conditions set out in legislation. If you exceed or fail to meet a requirement then you will require planning permission.
If not attached to the house, a car port will be treated as an ‘outbuilding’. A full list of requirements is available on our outbuildings common project.
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
In many cases, yes. Converting a single residential property (Class C3) into a small House in Multiple Occupation (HMO) for up to six occupants can often be done under permitted development rights, specifically under Class L. This means that planning permission isn’t usually required.
However, if your property is located in an area covered by an Article 4 Direction, permitted development rights are removed, and you would need to apply for full planning permission to change the use from C3 (dwellinghouse) to C4 (HMO).
Read more information about use class changes on Planning Portal
To qualify as permitted development some household building work projects – notably extending a house – must not exceed limits to the volume being added.
In England, the volume allowance mostly applies to loft conversions. You can read more on the Planning Portal.
Use the volume calculator to find out the volume of several loft conversion and extension types.
