TuffStuff® Standard Simulated Lead Flashing is fitted into the mortar line of the wall that joins to the flat roof so that water can run down onto the flat roof without any risk of water ingress. The lead flashing must be fitted over the top of either a D260 or D300 angle wall fillet. The mortar line should be chased out with an angle grinder. The lead flashing should then have a continuous bead of trim adhesive applied to the rear face so it can bond to the angle wall fillet. Once securely in place the chased out mortar line should be neatly pointed with a clear external grade silicone.