New regulations came into force on 30 September 2013 which changed the building work which can be done without needing to apply for planning permission. The Welsh Government has produced a technical guide, and a householder guide, available here, to help you understand how permitted development rules might apply to your circumstances.
You do not need to apply for planning permission for repairs, maintenance or minor improvements, such as painting your house.
If you live in a listed building, you will need listed building consent for any significant works whether internal or external.
If you live in a Conservation Area, a National Park, an Area of Outstanding Natural Beauty or World Heritage Sites, you will need to apply for planning permission before cladding the outside of your house with stone, artificial stone, pebble dash, render, timber, plastic or tiles.
Outside these areas, cladding may be carried out without having to first apply for planning permission provided the materials are of a similar appearance to those used in the construction of the house.
Disclaimer - Wales
This is an introductory guide and is not a definitive source of legal information. This guidance relates to the planning regime for Wales. Policy in England may differ. If in doubt contact your Local Planning Authority.