Root section, wind turbine blade and methods for producing and modifying a root portion of a wind turbine blade

A method for modifying a root portion of a wind turbine base blade installed in a wind turbine, wherein the root portion comprises an inner wall, an outer wall, a filler between the inner wall and the outer wall, an inner volume defined by the inner wall, and mounting inserts for mounting the wind turbine base blade to a hub of a wind turbine, wherein the mounting inserts are supported by the filler and extend in a longitudinal direction of the root portion and the wind turbine base blade, comprising:

• establishing at least one root portion hole through the inner wall and the filler to at least one mounting insert and/or through the outer wall and the filler to the at least one mounting insert;
• and
• installing a transversal holding arrangement in the at least one established root portion hole in contact with the at least one mounting insert;
• wherein the transversal holding arrangement is installed with at least one inlay beam extending from the inner wall and/or the outer wall into a mounting insert hole of the at least one mounting insert for holding the at least one mounting insert in the root portion during operation of the wind turbine blade;
• and
• wherein the mounting insert hole is provided as a through hole and the at least one inlay beam is located to extend from the inner wall through the mounting insert hole to the outer wall.