I'm building a porch with a pitched roof and canopy extending 900mm out over the front door. I'll be putting 100mm fg on ceiling and into soffit at side still allowing for efficient venting. I'm facing the gable end with wood and was ust a bit concerned about whether to put any kind of timber in the triangular area (2m wide by 1.4m high) above the door or to leave alone and allow the whole void area breath as one?