properly installed metal base flashing and counter flashing with new reglet joint. Although this is on a metal roofing job, the flashing sequence and installation is the same for every chimney flashing job. call Michael at 601 750 2274 for free advice and estimates. Bob at 601 212 5433 call from anywhere ..be happy to help …we have had calls from all over the US from Alaska to Costa Rico..even had one from London England ..