I need to enlarge drainage holes through two Bath stone parapets on my house in order to prevent them repeatedly blocking. The task is made more challenging by the hole being in an awkward corner and, because it's at an angle, the channel is about 9" long. Best way to go about this without risking damage to a historic house front? (Not listed, but in a conservation area. And historic, and valuable.)
The more frequently troublesome parapet only carries a 22mm length of copper pipe. The other has a zinc channel about 3.5" x 2.5" (see pic) and is less problematic but I'm aiming to sort both as part of the job of replacing their failed zinc flat roofs. What width should I be aiming for?
The more frequently troublesome parapet only carries a 22mm length of copper pipe. The other has a zinc channel about 3.5" x 2.5" (see pic) and is less problematic but I'm aiming to sort both as part of the job of replacing their failed zinc flat roofs. What width should I be aiming for?