You do not need to apply for planning permission for repairs, maintenance or minor improvements to your house such as painting.
Rendering or weatherboarding your house does not require planning permission as long as the materials used are of a similar appearance to those used in the construction of the house. If your property is currently finished in timber weatherboard and you wish to replace the existing weatherboarding with one of a similar appearance such as a cement fibre board then planning permission would not be required. However, if your property is finished in brick and you wish to render the property or weatherboard then planning permission would be required as the materials proposed are not similar in appearance to those already used in the construction of the house.
If your property is listed or you live in a Conservation Area, then planning permission and/or listed building consent would be required.
Further guidance can be found on the planning portal.