Maintenance on foundations generally does not require planning permission.
However, if you live in a listed building or designated area (conservation area, national park, area of outstanding natural beauty) you should check with your local planning authority before carrying out any work.
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.