Many standard external home patios, car port and verandah extensions are a basic flat or skillion roof structure abutted up against the existing building structure. Sometimes they are raised slightly above existing roof structure so any rainwater runoff falls directly onto the tile roof and sometimes the new structure overhangs the existing guttering so water from the existing and new structure both feed into the same gutter. However many installations we see the new Colorbond or Polycarbonate roof is run flush to the facia board below the lowest line of tiles and sometimes run in between the first and second run of tiles. Both of these types of installation create a high risk of water running or being blown in between the roof tiles and into the roof space causing water damage. Lead flashing cannot be used in with these materials because it reacts, so in the past soft zinc has often been used as a flashing. However, soft zinc cannot be stretched enough to create a water tight seal of the corrugated surface so the wind can easily blow water back up underneath it and into the roof space. So what’s the best solution for this problem?