How to put a flat roof on a garden room

Hi, Ive compiled 3 videos into one, so sorry if you've seen before! Just thought it might be easier if its start to finish, instead of jumping from one to the other. We are putting a flat roof on this garden room with a 75mm pitch over 3mtrs to create the fall. Timbers used are 5x2 c16, We can't use bigger timbers as this would bring our building over the 2.5mtr height limit. So, we are on the max size possible, they are at 400mm spacings and fixed with 90mm pas lode nails and upside down joist hangers over the steel. roof covering is OSB3 T&G boards that are fixed down with 63mm ringlet pas lode nails and glued with polyurethane glue on the joints. We then fix fascia and soffit all round to complete the roof structure ready for the rubber roof! Hope you enjoy and thanks as always for your support!