The present invention relates to a method of manufacturing a wind turbine blade having a first member with a first joining surface and a second member with a second joining surface. The method includes applying at least one resin barrier to one or both of the joining surfaces, and subsequently locating the first and the second members adjacent each other so that they are joined by the at least one resin barrier. Hereby at least one cavity is formed between the first and second joining surfaces, which cavity is delimited by the at least one resin barrier. Subsequently resin is filled into the at least one cavity, and the resin is cured. The first member may be a blade shell, and the second member may be a blade spar.