Glued laminated timber (GLT or glulam) is a structural lumber produced from wood cut into uniform strips (lamella), finger jointed to make long lengths, and bonded together with high strength adhesive, which is typically melamine (MF). The thickness of the lamella is usually 45 mm. For curved or arched beams, the layers may be from 6 to 45 mm, depending on the requirements. And glulam is available in a range of dimensions, from 80 to 1,280 mm high, 80 to 280 wide, and over 40 m long.

It is used in home construction, multi-story buildings, agricultural and industrial facilities, recreation and sports centres. It is suitable for the roof structure as a visible component (all knots are sound knots and knotholes are patched), main beams with large spans, columns and floor structures. The bending strength of depends on the tensile strength of the layers (lamellae) and finger joints between the assembled lengths. Spruce is the most commonly used timber, but pine, Douglas fir and larch are also popular – all types of timber may be used.

In additional to straight beams with a constant cross section, it is possible to make tapered beams, curved beam and pre-cambered parallel beams, double tapered or pinched cambered beams, fish beams, trussed girders and free forms (curved profiles). The same as solid wood, it machines well and can be pre-cut to profiles before arriving on-site, such as to marry with rafter and purlin profiles, or for joints (rafter notch, stepped, tenon, dovetail, log house).