(1)  Concrete slab
(2) Waterproof membrane epoxy bonded to the substrate either side of the expansion gap
(3) Expansion joint fitted directly over water barrier and centred over the expansion gap
(4) Downpipe connected to waterproof membrane
(5) Waterproof membrane bonded to the sides of the expansion joint and cross-linked to the membrane bonded to the substrate forming a completely watertight envelope