Abstract: A tool (1) for spreading adhesive over a substrate has a blade edge (4) with a set of spaced large indentations (5) and at least one set of spaced smaller indentations (6) extending into the blade edge. The smaller indentations extend into the blade less than any one of the large indentations and are interspaced between the large indentations. The blade edge is slid over the substrate to which adhesive has been applied and the adhesive is spread such that the large indentations form large ridges (20) of adhesive projecting from the substrate. The smaller indentations form smaller ridges (21) of adhesive projecting from the substrate and the smaller ridges (21) are interspaced between the large ridges (20). When a tile (23) is pressed into the adhesive the larger ridges (20) are compressed first, thereby broadening the ridge and pushing adjacent ridges into the smaller ridges (21). In this any void between ridges is more readily filled and a more uniform spread of keyed in adhesive is achieved.