I’m about to start work on converting and extending an old stone barn. Ground floor extension is due to be flashed into a round stone wall (external of turret style room) for a short section above the door (see picture). Surface of stonework is irregular and curved (see picture) which makes things tricky - especially with joints often being up to 2 inches further set back than the stones in some places (see picture). A regular stone saw wouldn’t get deep enough to flash - any suggestions welcome?
