Have an attached garage with a flat roof. The roof serves as a veranda for the rest of the house. Decking and railing on top of the roof. Now want to lay metal roofing sheets on top of the felt and then new decking. How to attach the wooden railing to this roof? Use the decking in some way, but if so how? The roof is about 3x8 m. Therefore, do not want to make holes in the metal roofing. Tips on how to attach the wooden railing.