A perimeter frame and graduated spacer-nailers are mounted beneath the deck joists so that the plane in the ceiling slopes a little (not less than one/four inch for every foot) faraway from your home towards the joist header. #azek #azekbuildingproducts #timbertech #timbertechtakeover #timbertechtakeover #timberwolfpack #keylinkrailing #aluminum #railing #pvc #Wooden https://g.co/kgs/S8K82yS