During the planning of PM4 there had been considered building a fifth paper machine, and a lot was reserved for the machine. After PM4 was operational, management decided to go for further expansion. PM5 was built by Wärtsilä and became operational in July 1968. It had an annual production of 70,000 tonnes and initially operated at per second. Investments were about NOK 100 million. PM4 and PM5 were by far the largest paper machines in Norway until the 1966 opening of Norske Skog Skogn. PM1 was converted to produce fine grade paper based on pulp from birch and spruce. By 1970 the factory's output reached 220,000 tonnes annually.