National and European standards do not contain any guidelines for the manufacture or quality control of glued laminated timber manufactured in broad-leaf timber. Firstly, glued laminated timber made of suitable broad leaf timber achieves extremely high strengths. Secondly, use of large sections with a deciduous wood surface is an interesting alternative to the softwood types usually used.
For this reason, the Studiengemeinschaft Holzleimbau e.V. (English equivalent: glued laminated timber association) has applied for an technical approval for Glued laminated timber made of beech and glued laminated timber made of a combination of beech and spruce, so-called hybrid beams made of beech/spruce, and has since received this.
Members according to German technical approval Z-9.1-679 may currently only be used in Service Class 1 in accordance with DIN 1052: 2008-12 or DIN EN 1995-1-1:2010-12. Glued laminated timber treated against biological attack or with fire-retardants is not covered by the technical approval.
Glued laminated timber made of beech and hybrid beams made of beech
Combined glued laminated timber member made of beech tested at the University of Karlsruhe