A frame assembly is made up of a number of strips and a frame member, which has a channel defined by side walls and a bottom wall. A first strip located in the channel has a terminal end section defined by a return flange so that the terminal end section surrounds the peripheral edge of a rigid stainless-steel screen. The wall has projections and recesses which cooperate with respective recesses and projections in the first strip to position the first strip and inhibit its removal. A locking strip and the wall have cooperating oppositely directed teeth to drive the locking strip into position and prevent its removal without destroying the teeth. Both strips have a screen contact region made up of ridges. The first strip is made from soft PVC while the second strip is made from rigid PVC or a co-extrusion being softer on the screen contact side.