Glulam is the popular name for glued laminated timber whereby aesthetically attractive structural timber components of large cross-section and long lengths can be fabricated from small cross-section boards (laminates) in commercial sizes. A glued laminated component comprises small cross-section boards, laid up so that the grain is parallel to the longitudinal axis, in contrast with plywood where the grain is alternately parallel and perpendicular.
The need for preservative treatment will depend upon the service class, the life required and the species of timber used. Generally, in environments where the moisture content of the glulam is less than 20% it will not be necessary to treat the laminates or the finished components against fungal attack. The risk of insect attack for internal timbers will need to be assessed. In external locations or other situations where the moisture content in service is likely to exceed 20%, either the timber must be naturally resistant to decay, or preservative treatment will be required.
Environmentally Friendly
A 305mm x 165mm steel ‘I’ beam has the equivalent performance of a 550mm x 135mm softwood glulam beam but requires six times the energy cost to produce. A comparable 400mm x 250mm reinforced concrete beam requires five times the energy cost to produce. Add to this the pollutant by-products of these wasteful processes and steel and concrete structures are even more environmentally undesirable.
Energy Efficient
Glulam is also energy efficient in use. The well known insulation property of timber eliminates the risk of cold bridging where the frame may penetrate external elements of the structure.
A structural steel beam may be 20% heavier and a concrete beam 600% heavier than an equivalent glulam beam
Chemical Resistance
Timber and the synthetic adhesives used in bonding glulam have a remarkable resistance to chemical attack and therefore glulam is often chosen as the preferred structural material for buildings such as salt barns, water treatment plants, etc.
Economical
A direct cost comparison shows that it is competitive with other structural materials; and the lower weight of glulam leads to savings on foundations, transport and erection
Good Looking
The natural appearance of glulam is sufficiently attractive to make it eminently presentable with no cladding – indeed, used as exposed beams, glulam adds to the aesthetic appeal of a structure.
Versatile
Glulam can be used for roof, lintel and floor beams, columns and rafters in almost any type of structure
As a result of the low moisture content dictated by the bonding process and the random laying-up of the laminates, the finished component will usually have better dimensional stability and suffer less from checks and deformation than solid wood sections, which often have to finish their drying in service. The low coefficient of thermal expansion of timber compared with steel is also an advantage in that expansion joints can be omitted or simplified, even in large structures. Similarly, timber has better resistance to corrosive industrial or marine atmospheres than either steel or concrete. The considerable savings in maintenance costs on exterior structures, such as bridges, make the use of glulam a very attractive proposition to specifiers and owners.
When subjected to fire, large timber sections have greater resistance to loss of structural integrity than steel or pre-stressed concrete. This resistance is provided by a layer of charcoal which forms around the surface of the section during exposure to fire. The rate of charring of different species of timber is known and therefore the performance and endurance of timber in fire is predictable.
It is generally presumed by specifiers that glulam is ideally suited in situations where its aesthetically pleasing appearance gives it an advantage over other structural materials. It is true to say that the sheer beauty of glulam, coupled with its natural empathy with special environments, makes it eminently suitable for use in buildings where it is beneficial to generate a relationship between the audience or participants and the building envelope. Concert halls, swimming pools, leisure and sports complexes, gymnasia, churches, and schools are all obvious contenders.
The Glulam Effect
- Glued laminated structural timber.
- Curved or straight to any transportable size.
- For simple or complex structures.
- Takes proprietary stains to suit any decor.
- The energy efficient renewable resource.
