i have a nice view and have planning permission to enlarge an existing dormer to take advantage. the new window would be 4.5m long and 1.4m deep, i want as much view and as little window frames as possible any advice where i can get such a window or do i have to have 2 with great big lump in middle of my view. also doe sanyone know if i will need steel for that span or should i ask engineer to do calcs.