Our cabins come with uPVC Gutter Drip Plate, which is a two-part accessory attached to the flat edge of the roof which creates an angle to direct the water off on your log cabin.
The supplier has comprehensive videos advising how to fit these to your roof and more information can be found in your instruction booklet: https://www.permaroof.co.uk/news/video/fitting-a-drip-plate-to-a-flat-roof-gutter-edge
Please note this is not the same as guttering, which is not supplied with the log cabins.