Whether you need to submit a planning application for the works you want to carry out is dependent initially, on whether the works amount to ‘development’ and then secondly, whether the works are in a class of ‘permitted development’ which provide an automatic grant of planning permission so that a formal planning application is not required.
Development is defined under the 1990 Town and Country Planning Act as "the carrying out of building, engineering, mining or other operation in, on, over or under land, or the making of any material change in the use of any building or other land."
The starting point is to assume all buildings and engineering operations require a planning application to be submitted to the local planning authority.
The contents of this factsheet are intended for general information purposes only and should not be relied upon nor used as a substitute for planning advice from the relevant local planning authority. You should always consult with your local planning department as to whether your scheme needs planning permission before you start any works.
This factsheet was developed by Social Farms and Gardens through the Tyfu Cymru project.
Social Farms & Gardens is a UK wide charity supporting communities to farm, garden and grow together. Lucie Taylor is a chartered town planner of 20 years and working for Social Farms and Gardens for the last 7 years.
 You can find details of your local planning authority in Wales here - https://gov.wales/find-your-local-planning-authority