// From tree
This is where it all starts. Selecting the correct species to produce the best Glulam. The resultant timber needs to be easily bonded and structurally consistent
Spruce / European Whitewood (Picea Abies)
Norway or European spruce is grown widely throughout Europe and is a large fast-growing coniferous tree. Mature trees reach an average height of about 36m. When converted the timber is pale cream, strong straight grain with a fine texture
Pine / European Redwood (Sinus Sylvestris)
Pine is also extensively grown throughout Europe and grows at a slightly slower rate than Spruce with an average height for mature trees at around 30m. The resultant timber is pale but has a greater variation between summer and winter growth giving a slightly more visible grain structure.
// To Log
Trees are felled when they reach their economically mature stages (40 to 150 years) this also depends on tree species and environmental factors.
Carried out in the winter months due to a lower moisture content, felled trees are replaced with saplings to provide a sustainable source for future generations. The trunk is usually debranched and cut into a butt log, middle log, top log and one to three sections of pulpwood. Crown and branch wood can be collected up to be chipped and used as forest fuel, which is used for energy regeneration. Logs are left in the forest allowing time for the ‘free’ water content to evaporate, reducing the weight of the logs lowering the cost of handling and transport to the sawmills.
// To Timber
Timber conversion is the process of turning a log into planks or boards.
The logs are scaled and debarked, logs are sorted by species, size and end use, the logs are sawn into unfinished planks/boards. The timber planks/boards will then be trimmed removing irregular edges leaving four sided timber and cut to standard timber lengths. The timber planks are then seasoned, the process by which moisture content in the timber is reduced to required level. By reducing moisture content, the strength, elasticity and durability properties are developed. A well-seasoned timber has 15% moisture content in it. Timber is then strength graded and can be carried out visually or by machine. Visual strength grading uses the grader’s experience across a number of different factors to predict the load a piece of timber will be able to carry in service. Machine strength grading is best suited to high volumes of timber where the species and cross section are not changed very often. Machine grading is based on the relationship between strength and stiffness. The machine grades each piece and stamps it with the appropriate mark.
// To Glulam
A glue-laminated timber is an engineered wood product, meaning it is made from wood but is machined and assembled to precise specifications to create a predictable, dimensionally stable building material.
The timber that forms the lamination’s are graded for strength and in the case of our glulam stock in the main GL30c . The timber will be strength class T22 (between C35 & C40) in the outer lamination’s, and T14 (equivalant C24) on the inner. The timber at time of lamination will have a moisture content of 12% to 14%, during storage, manufacture and curing the temperature and humidity is tightly controlled.