Resource efficient bio-based interlocking of CLT – step 1

The project ran between November 2021 and March 2022.

The project aimed to test basic assumptions about a newly developed joining technology for CLT (Cross Laminated Timber). The goal of the technology is to replace the current screw joints in CLT during assembly.

The project was expected to confirm that the new joining technology has

  • conditions to be manufactured with sufficient precision
  • has sufficient joint strength and
  • that the building elements can be joined together with the help of a construction crane.

The technology has several benefits, such as reduced C02 footprint, better total cost for CLT, increased joint precision, edges without screw holes, increased gender equality at the construction site and an eliminated work injury risk. Moreover it facilitates reuse of joined panels. The competitiveness of CLT is substantially improved and significant growth is expected.

Stakeholders throughout the value chain will benefit from the technologies. Engineers will gain by faster engineering process and increased security in actual joint performance. Architects access completely hidden joints and reduce CO2 footprint. CLT manufacturers may increase turnover and margin on same volumes sold. Construction site work is gender equal and faster with reduced work injury risk. Property owner may benefit from the possibility of reusing the material. End users will gain by reduced risk of smell and sound emissions.

Hypotheses that have been tested with full scale equipment/parts:

1) Today’s machine equipment probably does not meet machining tolerances, but reasonable adjustments can be made to solve the problem. Test with test milling, adaptation of machine park with temporary indicative solution and measurements showed that the technology is industrially applicable with no or modest adjustments to existing commonly used CLT manufacturing process.

2) The joint is expected to meet the load requirements that can be set on the joint. Load test with scalable test elements.

3) The assembly is expected to be possible using today’s construction cranes, based on tests with full-scale building elements.

The drafting process for the scheduled PCT application of the technology has gained important input in the project. Based on the project results, the project participants have decided to incorporate a real estate company in the further validation work, aiming to use the technology in a public multi story building.


Martinsons Byggsystem AB and Moditri AB.


The project’s total budget was 948 000 SEK.

The picture shows Sara Kulturhus, which is a good example of the application environment.

Read about Resource efficient bio-based interlocking of CLT – step 2.