Production and Technology of Cross Laminated Timber (CLT): A state-of-the-art Report

Cross laminated timber (CLT) has been developed into a worldwide well-known and versatile
building material. Progressive rates in production volume and distribution can be observed
currently. In fact CLT opens new horizons in timber engineering thanks to its laminar structure
which makes it well suited for use in constructions of that type which had been subject to mineral
building materials like concrete and masonry so far.
After a short introduction this contribution aims on demonstrating current production processes
used for rigidly composed CLT. In chapter 2 the process steps are individually described and
essential requirements as well as pros and cons of various production techniques are discussed.
Latest results of R & D and developments as well as innovations in production technology are
presented. In chapter 3 test and monitoring procedures in frame of the internal quality assurance,
known as factory production control (FPC), are presented. Thereby diverse regulations as
anchored in technical approvals for CLT as well as in the CLT product standard prEN 16351 [1]
are discussed. Additionally, some technological aspects of the product CLT together with a
comparison of geometrical and production relevant parameters of current technical approvals in
Europe are provided in chapter 4.
In the final discussion the main content of production and technology is presented in a condensed
way. An outlook in regard to current and future developments as well as concerning the ongoing
establishment of the solid construction technique with CLT is given. The product CLT comprises
an enormous potential for timber engineering, but also for the overall society. Standardisation and
further innovations in production, prefabrication, joining technique, building physics and building
construction makes it possible that timber engineering achieves worldwide success