Chimney stacks are susceptible to water ingress in many roofs. Often failed pointing, flaunching and flashing and/or the lack of lead soakers or a chimney tray are the cause. Often this can be addressed by re-pointing of stone or brick work and re flaunching the top. In high exposed areas the stacks may be rendered or pebble dashed. In other cases the lead flashing has cracked or has been poorly installed without the correct soakers and saddle joints and so would need to be replaced.
