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
There is no single legal definition of "habitable room", as its use and meaning are subject to context. Generally, a habitable room is a space in a building that is designed for people to live, sleep, or spend extended periods of time in, but does not include bath or toilet facilities, corridors or utility rooms.
Categorising land and buildings according to their type and purpose is known as Use Classes.
A 'Change of use' can be within the same Use Class or from one Use Class to another.
You will need planning permission for certain changes to the use of a property such as changing from a residential use to a business use. However, it is possible to change use between some classes without having to make an application for planning permission.
Depending on the specifics of any proposed change of use, including any building work associated with the proposal, an application for planning permission or prior approval may be required.
An application for full planning permission for a change of use is often required when changing from a house (use class C3) to a residential institution (use class C2). This is due to the increased activity which a C2 use would have on the local street area through the addition of visitors, staff and changes to parking.
Read additional information on use classes and changes of use.
Yes, but you will need to obtain planning permission. Converting a detached garage into a self-contained living space, such as annexe, studio flat, or retail unit, represents a material change of use, particularly if it will function independently from the main house. This is because the garage would no longer be used in connection with the main dwelling and would effectively become a separate residential unit.
Under the Town and Country Planning (General Permitted Development) (England) Order 2015 (as amended), you have a general permission to install an antenna up to a specific size on property without the need for planning permission. This general permission depends on your house type and area. Your local planning authority can give you more advice.