Yes, under permitted development, a new dormer must not be higher than the existing highest part of the roof. It should also have materials that are in similar appearance to the existing roof. Additional limits apply in conservation areas and on listed buildings. Read about planning permission for loft conversions on Planning Portal
A single storey rear extension can fall under permitted development, meaning planning permission may not be required providing it meets certain criteria.
In terms of height, the extension must:
Read about planning permission for extensions on Planning Portal
Planning permission is not required for the installation of a stair lift, however, if you live in a listed building, you will have to apply for listed building consent for any significant works, whether internal or external.
Stairlifts must be installed in line with BS EN 81-40:2020 which focuses on safety requirements for the installation of stairlifts.
Inserting new windows which look similar to those previously used in the house will often not require planning permission. Some rules apply to new additions, for example if they are on an upper-floor side elevation they must be obscure glazed and non-opening or more than 1.7 metres above the floor.
Installing a new bay window on the front elevation would require planning permission as it is classed as a forward extension.
If you live in a listed building or conservation area you should contact your local planning authority.
Any new openings will have to comply with building regulations, this may impact thermal heat loss, structure, ventilation and fire safety.
You can use a member of a competent person scheme to complete any work, this will ensure that the work is completed in-line with regulations.
A council’s planning department, known as the local planning authority (LPA), is the local government body responsible for managing and overseeing the planning system in a specific area.
You can use the search tool on Planning Portal to find the contact details for any local planning authority in England and Wales.
Certain types of development are granted planning permission by national legislation without the need to submit a planning application. This is known as 'permitted development'. In order to be eligible for these permitted development rights, each 'class' specified in the legislation has associated limitations and conditions that proposals must comply with.
One such condition on certain classes of permitted development is the need to submit an application to the local planning authority for its 'prior approval; or to determine if it’s 'prior approval' will be required.
This allows the local planning authority to consider the proposals, their likely impacts in regard to certain specific factors (e.g. transport and highways) and how these may be mitigated.
For more information on prior approval, read guidance on prior approval consent types.