The Rubner Holzbau glulam beams are in general produced using Nordic spruce. For special production – above all for outdoor applications – woods such as larch or douglasia (a species of pine) are also used.
The strips for glulam production, cut from fresh roundwood, artificially dried and selected according to the strength class, are sawn at the Group sawmill and supplied just-in-time to the production facility. Here they are stacked under vacuum and go on directly to the completely automatic production line. After a quality control system, with elimination of defects (large knots etc) through scanner detection, a continuous beam is produced, in the required length and with finger joints, which is finally planed and glued. The beam produced with this process, of length up to 50 metres, is then shaped to the required form in a numerical control press, respecting the prescribed threshold values.
After the phases of hardening and planing, the beam is finished according to customer requests; this is done in large part by numerical control robots that cut the raw beams according to the CAD project. The processing as to customer requirements is facilitated by the use of fixed-axis laser drilling and milling units. The consequent detailed control guarantees dimensional precision for the wood elements, which have tolerances even smaller than those foreseen for structural steel components. The beams are then painted and impregnated; after that, the steel components are fitted.
The glulam production at Rubner Holzbau is subject to constant external control by accredited international agencies, which also check the validity of the national and international certificates and quality marks, as well as the conformity with the prescribed quality standards.