// Glulam Specialist
Glulam is the most environmentally friendly product for long span structural use. As well as being very efficient to produce – the energy required to produce a glue-laminated beam from the log is only a fraction of the energy required to produce steel or concrete – it can also be reused or recycled. Glulam has superior earthquake resilience, withstands aggressive environments and is more predictable in fire than any other structural construction material. In relation to its weight, glulam is one of the strongest construction materials. Glulam can be made into virtually any shape. Section sizes are almost limitless and usually the only constraints are access and transport. The total cost of glulam construction is often lower than other construction materials and can be worked with simple hand or machine tools. The only maintenance required when used internally is that required by any surface coatings applied.
There are many factors to consider with cost comparisons. Glulam weighs less than steel of comparable strength. Glulam is lighter to transport and install than steel. Glulam is far more attractive and easier to work with on site than steel. Glulam is produced from sustainable sources. Glulam is designed with a known charring rate in fire, steel would need to protected.
Otto Karl Freidrich Hetzer, a German carpenter and inventor, obtained a patent in 1901 for a straight beam composed of several laminations bounded with adhesive. Hetzer further refined his work, and five years later was given a patent for curved glued laminated timber construction.
How do you calculate the size of the beam you require?
As well as being strong enough to carry the loads applied to it, it is important to check any deformation of any structural member, such as deflection, does not impact other materials or finishes. This applies to Glulam as much as any other material. Knowing what load is applied, how it is applied and what each member is doing within the overall context of the structure is vital. This is why we state that our load/span tables are for estimating sections only and do not replace full calculations. We can offer a full structural design service (fees apply).
What surface treatment should you use on glulam?
Internally, there is no need to coat Glulam unless you want to alter the appearance for aesthetic reasons. hings to consider with coatings. Glulam, like all timber, moves with changes in moisture content so the beams should be as close to service conditions before coating. If coated before the timber dries to service moisture levels, small fissures, which may occur on drying, will show the base material colour and can break varnish finishes. When used externally, seek advice from a specialist coatings company to agree a coating system build up and maintenance regime suitable to the exposure conditions.
How far do
Large span widths are no problem for glued laminated timber. However, the limits for very long glulam components are soon reached when it comes to transport and narrow construction site access roads - although beams in excess of 30m have been used in UK.
Although all our Glulam is manufactured with adhesives suitable for external use, there are other things to consider when doing so. Standard beams suitable for service class 1 (indoor heated) and 2 (covered and unheated) are made from lamella up to 45mm thick. For service class 3 (external exposed to weather but not in ground contact) only beams with a cross sectional area of less than 60,000 mm2 can used with this lamella thickness. Larger section beams should have a maximum lamella thickness of 35mm which can be made to order.
How safe are
in a fire?
Glulam performs very well in fires. This is due to the way in which timber chars at a known rate and does not deform like steel. Fire performance of glulam has been the subject of extensive research. Structural glulam members can be designed to retain structural integrity after timed exposure to fire based on the charring rate of 0.7mm/min on exposed faces.
Glulam beams are very efficient to produce. The energy required to produce a glue-laminated beam from the log is only a fraction of the energy required to produce steel or concrete. Glulam has no negative environmental effects. Once the glulam product has reached the end of its life, if carefully dismantled could be re-sized and or re used.