The original plan was to support the new roof on a timber post in the middle of the kitchen. It made sense, but when I investigated the roof space I could see that adding Jack trusses to the existing girder Truss and building a standard hip section would open up the new extension without the need for a post in the middle of the floor. After chatting to the truss manufacturer I was told we would need to consult an engineer to manually calculate if the older structure was compatible with their new