Yes, you require scaffolding to replace windows or install new windows on the second storey of a building or higher.
The scaffolding to be used will depend on how high the windows are from the ground. If the roof window can be temporarily fitted from the inside, then there’s no need to have scaffolding due to the ease of access.

The scaffolding ensures that the builders can easily and safely reach the area where they’re installing the windows. This ensures the window installation is done more efficiently. The builders should be well trained on how to handle the windows to prevent accidents on themselves and anyone below.
Do you need scaffolding to install velux windows
Yes, you need scaffolding to install Velux windows if the installation is being done from the outside. The scaffolding will not only provide easy access it will also ensure that the builders can safely install the windows. Also known as roof lights or roof windows, Velux windows are the easiest and cheapest windows to install.
Do you need scaffolding to access your roof like Chimney?
For most roof windows, you’ll find that the installation can be done from inside hence scaffolds won’t be necessary. Depending on where the property is located in the UK, scaffolding rules and regulations will prevail. Your location will also determine whether it’s possible to erect scaffolding or not. The height of the building will determine the most suitable scaffolding type to be used.
Aside from following all the building regulations, the homeowner, scaffolder, and contractor should ensure that The Work at Height Regulations 2005 are adhered to the latter. This will ensure that any accidents or hazards are avoided since the builders will have a safe working platform to do their job. Depending on the type of windows you are installing, your contractor should let you know whether scaffolding is necessary.