Does a retractable pergola need planning permission?

In most cases, no. A retractable pergola is generally treated as a temporary structure and can usually be installed without planning permission, much like an awning, particularly when kept under 2.5m high and where it doesn’t occupy more than around 50% of the available outdoor space. For most people the size required is usually well below ‘permitted development’ rules for extensions and conservatories anyway. Exceptions will inevitably apply in conservation areas and for listed buildings and commercial applications. If in doubt, a quick call to your local council will confirm your position.