hi everyone. looking at my plans for a 6mx3m single storey exstension,its going to have a warm flat roof. i have to place a r.s.j into the existing wall and bolt a wallplate into the steel for the roof joists.and transfer that level to the newly built brickwork at the front and two sides. my problem is when the warm roof is on there will be a pitch created by the firrings and insulation. the then two side walls wont be level when i come to fit the facia. how do i get round that problem. and also is there a cheaper version of the kingspan 96mm thermaroof tr31 its very expensive. 
