Permitted Development (PD) rights allow you to install roof windows as long as they do not project more
than 150mm from the roof plane.
However, you should be aware of several exceptions. If your property is located in a conservation area
or is currently listed, you will need to obtain planning permission before installing a roof window.
Checking with your local planning authority before starting the installation process is a good starting
point. It's the best way to figure out whether or not you need planning permission for your specific
project.