Experimental study on the vertical interface of thin-tile masonry

•The behaviour of mortar-tile vertical interface was analysed using the DIC technique.•The multi-leaf wall masonry compressive strength equation was suitable for a two-leaf thin tile.•Failure mode of thin-tile masonry is characterized by cracking at the mortar-tile vertical interface.•Uniaxial compressive strength in the detachment is relevant for thin-tile masonry.•In thin-tile masonry, the load is mainly carried by the thin-tile leaves.