The present disclosure relates to a spar cap (10) for a wind turbine blade (1000) comprising: a plurality of spar cap layers (20) and a first interlayer (30) arranged between the first spar cap layer (20a) and the second spar cap layer (20b) and comprising: a number of first interlayer areas (31), including a first primary interlayer area (31a), comprising a first number of interlayer sheets (33) comprising a first plurality of fibres (35); and a number of second interlayer areas (32), including a second primary interlayer area (32a), comprising a second number of interlayer sheets (34) comprising a second plurality of fibres (36), wherein the first number of interlayer sheets (33) is of a different characteristic than the second number of interlayer sheets (34).