Glulam is manufactured from small pieces of timber, bonded together to form the desired size of beam. Due to this, virtually any size of beam can be achieved - the main limitation is the practicality of transporting. Timberbond has manufactured solid beams 2.0 metres deep (6.6 ft) and over 400mm wide (15.7") To avoid the difficulty of transporting long lengths (generally over 20.0 metres (65 ft), connections can be designed to allow for reconnecting on site.

The size of a glulam beam is dictated by the stresses and loads being exerted on the beam. For complicated or unusual designs, engineering calculations need to be conducted to determine the size of the beam. For standard domestic situations, generic tables have been compiled. For an indication of these beam sizes, please refer to the downloadable generic Glulam span tables (hyperlink to the PDF files)