A METHOD AND A KIT FOR FUSING A MEMBRANE TO A BASE SURFACE OR TO OTHER MEMBRANES FOR SEALING A JUNCTION FORMING PART OF A BASE OF A CONSTRUCTION TO PREVENT RADON PERMEATION

1. A method (1000) for fusing a membrane (10) to a base surface (60) or to other membranes (10) for sealing a junction forming part of a base of a construction (20) to prevent radon permeation, the method (1000) comprises steps of - cutting (1100) the membrane (10) comprising a membrane surface (14) into one or more membrane pieces (12) fitted for the junction having a junction structure, wherein the membrane (10) comprises of polyisobutylene, - adjusting (1200) the one or more membrane pieces (12) to shape the junction structure, wherein an overlap (30) comprising two facing surfaces is established between each adjacent membrane piece (12) or between the membrane piece (12) and the base surface (60), - applying (1300) a solvent to at least one of the membrane surfaces (14) engaging in the overlap (30), wherein the solvent partly dissolves the surface (14), - pressing (1400) the overlapping surfaces together, wherein the one ore more membrane pieces (12) fuse together or the membrane piece (12) and the base surface (60) fuse together.