the roof is whats known as a comb stephen,basicley transom/mullion sections welded together and makes for a cheap roof,the rubber is just a wedge gasket that pushes the external bead outwards to make,in this case the polycarbonate secure,slap bash is correct as in running a bead of clear silicone between the bead and polycarbonate and then pushing the wedge gasket back,don't walk on these roofs though as they are not load bearing