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.
These work well in conjunction with guttering should you choose to add this to your 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
As we do not supply guttering, we are somewhat limited in what advise we can offer, but if you have any questions, please feel free to reach out to our team at hello@powersheds.com.