The invention provides a method of manufacturing a spar (1) for a wind turbine blade. The method comprises steps of providing at least two caps (2a, 2b), each cap forming an intermediate portion (4) between two end portions (5), where the end portions each forms a cap joint surface portion (6) along a longitudinal extending edge of the end portion and the intermediate portion forms an outer surface portion (7) of the spar, providing at least two webs (3a, 3b), each web being provided with web joint surface portions (8) along opposite and longitudinally extending edges, and connecting the joint surface portions of the caps with the joint surface portions of the webs to form a tubular configuration of the spar. The intermediate portions and the end portions are provided so that they comprise different materials.