A method is provided for roll-forming a sheet metal strip (35) by driving the sheet metal strip through a row of forming stations (17, 18) having pairs of rollers (19, 20; 29, 30) directed towards each other and both holding the sheet metal strip therebetween and forming the sheet metal strip over roller edges. In every second forming station (12), two angles (41, 42) are gradually formed and in every second forming station two other angles (43, 44) are gradually formed.