High performing rails from CLT panel waste for advanced prefabricated volumetric timber structures

Important results from the project

The main goal of the project was to produce, test, and evaluate a product made from leftover materials from the manufacturing of cross-laminated timber panels, known as CLT panels. Extensive experimental tests, conducted both in the lab and in the field, show that the wooden rail produced has exceptional short- and longterm performance. The rail is about 5 times stronger than existing products. Additionally, it is more dimensionally stable and has a lower equilibrium moisture content.

Expected long term effects

Today, the byproduct created during production of cross-laminated timber panels, from door and window openings, is mainly used as biofuel. In this project, we demonstrated that this byproduct can instead be successfully used as rails in the construction of prefabricated timber houses. This application significantly increases the value of the byproduct and turns it into a long-lived component. The new CLT-rail significantly reduces issues with vertical deformations in tall timber buildings.

Approach and implementation

CLT rails were manufactured at Stora Enso´s facility in Gruvön and then distributed to other project partners. They were used for short- and longterm experiments at Karlstad University. CLT-rails were also integrated into standard prefabricated wall elements or timber modules by participating companies. The timber houses built with CLT rails were equipped with instruments, and field measurements—still ongoing—were conducted, with vertical displacements being recorded around every five minutes.