An exemplary oil transformer insulation module includes at least a first flat layer and a second layer adjacent and substantially and parallel to the first layer. The first and second layers include planar first insulation material and are connected to and spaced apart from a third corrugated layer that is arranged between the first and second layers. The third layer includes planar second insulation material, has lateral edges, and is corrugated such that all the cavities formed by the corrugated form can be flooded with a liquid via the lateral edges.