Planning permission is not normally required for fitting insulation (where there is no change in external appearance).
However, if the building is listed or is in a conservation area you should consult your local planning authority.
Find your local planning authority (https://www.planningportal.co.uk/find-your-local-planning-authority)Find your local planning authority
Find a Trade Professional
Use our partner directories from CIAT, FMB, RIBA, or RTPI to find an chartered architectural technologist, builder, architect or planning consultant to help with your project or development.
Find a professional (https://www.planningportal.co.uk/planning/planning-applications/find-a-trade-professional)Find a professional
Make an application (https://www.planningportal.co.uk/app/applications)Make an application
Planning consultancy calculator (https://www.planningportal.co.uk/permission/home-improvement/planning-consultancy-calculator)Planning consultancy calculator