What is the correct width for mortar at verges?
BS 8000: Part 6: 1990: Workmanship on building sites states ‘Provide about 100 mm of mortar width and bed tiles solidly and finish edge neatly’. The more surface contact of mortar the less likely the verge tiles are to fail. However it is essential that the bedding mortar does not come in contact with the ends of the tiling battens. The width of the undercloak is normally 150 mm of which 50 mm laps under the batten ends. If 100 mm width of mortar is placed onto the undercloak it will touch the batten ends. Once the tiles are bedded into the mortar it will spread by a further 25 mm around the end of the battens. Therefore a 50 mm width of mortar should be applied which will spread to 75 mm when bedded.
