When attaching clinker bricks, the best results are achieved by laying on the so-called. empty joint. With this method, the joints between the bricks are not completely filled. Only after the mortar has hardened, the joints are filled in by shaping them appropriately. Bricklaying in this way requires the application of mortar in a strictly defined amount. There can't be too much of it, not too little. This will be facilitated by a special sliding frame made of thin slats. Apply the mortar inside it and pre-level with a trowel.