The invention provides a method of manufacturing a spar for a wind turbine blade. The method includes providing at least two caps, each cap forming an intermediate portion between two end portions, where the end portions each forms a cap joint surface portion along a longitudinal extending edge of the end portion and the intermediate portion forms an outer surface portion of the spar, providing at least two webs, each web being provided with web joint surface portions 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 caps are provided so that the end portions extend transversely to the intermediate portion and the caps are arranged relative to each other so that the end portions of one cap extend from the intermediate portion towards the end portions of another cap.