In Ireland, you generally need planning permission for various types of development and construction activities. The exact requirements can vary depending on factors such as the location of the project, the type of development, and local zoning regulations. Here are some common situations in which you typically need planning permission:

1. New Buildings: Planning permission is usually required for the construction of new buildings, including residential, commercial, and industrial structures.
2. Extensions: If you plan to extend an existing building, such as adding an extra room or expanding your home, you will likely need planning permission.
3. Change of Use: Changing the use of a building, such as converting a residential property into a commercial one, often requires planning permission.
4. Demolition: Demolishing a building may require planning permission, particularly if the building is protected or located in a designated conservation area.
5. Change of Land Use: If you intend to change the use of land, such as from agricultural to residential, planning permission is generally required.
6. Subdivision of Land: Subdividing a piece of land into multiple plots for development usually requires planning permission.
7. Protected Structures and Conservation Areas: Special rules apply to protected structures and buildings located within conservation areas. Even minor alterations may require planning permission.
8. Wind Turbines and Telecommunications Masts: Erecting wind turbines, telecommunications masts, or other tall structures typically requires planning permission.
9. Development in Sensitive Areas: If your project is located in areas of environmental sensitivity, such as near a river, lake, or coastal zone, you may need special permissions.
10. Large-Scale Projects: Major development projects often require an Environmental Impact Assessment (EIA) as part of the planning process.

It’s important to note that these requirements may change over time, and local planning authorities may have specific regulations and guidelines that apply to their jurisdiction. Therefore, it’s advisable to consult with your local planning authority or a qualified architect or planner when considering a development project in Ireland. They can provide guidance on whether planning permission is required and help you navigate the application process if it is necessary. Failure to obtain the required planning permission can result in enforcement action, fines, or even legal consequences.