Basic anatomy of glulam

Glulam stands for glued-laminated timber. It was first introduced to the public in the early 1890s in Europe and is still popularly in service today.

Basically, glulam is an engineered product which is made up of several layers of structural timber bonded together with adhesives to make bigger pieces. A variety of wood species is used to manufacture glulam. The consisted boards are laid in a way so the grain is parallel to the horizontal axis. Such process produces glulam members which have larger size and longer length and can be easily worked to curve or straight.

Glulam possesses the natural colour of wood, with its sophisticated appeal. This invention was born as an alternative of pre-designed shapes and dimension for woodworkers, instead of dealing with solid sawn timber of unusual shape or in large size.

A popular choice for environmentally conscious individuals

One would think engineered products that involve chemicals like adhesives would be harmful for our environment. However, when it comes to glulam, because of its good workability, the production of this wood-engineered product requires much less energy compared to that of steel or concrete. Another bonus is that glulam has comparable or superior strength and weight to either material. Furthermore, the concept of glulam manufacturing makes use of otherwise wasted wood, which makes it reasonably ecological for this reason.

Longstanding performance record

There are plenty of reasons why glulam remains popularized for over a century now. Thanks to specialized factory processes, glulam manufacturers can machine glulam products free of defect knots caused by manufacturing. This translates into greater strength as the wood boards are designed to have their sloping grains around the knots removed.

Compared to steel and concrete, wood products have a greater strength to weight ratio. For instance, in case of beam sizes, the strength of glulam is approximately 1.5 more than to double that of steel of the same load bearing capacity. A quick note: a beam is a horizontal or sloping structure designed to carry vertical loads. This characteristic of glulam works in favor of many home builders as manhandling a beam into a roof or loft space becomes feasible.

What's more, glulam is a popular choice for residential applications of harsh environments due to its high resistance to aggressive environmental pollution, and also chemical attack. Glulam structure can be worked during installation so that fungal or insect invasion can be prevented.

One particular noble quality of glulam is its fire performance. Glulam performs exceptionally well when temperatures reach 1,650 degrees or higher. The temperature glulam member is able to withstand can be raised, as a result of the charring increasing the insulation of the glulam member. Additionally, on cross-section most of glulam will remain in one piece upon contact with fire and continue to support the load of whatever structure. This means glulam will not twist nor buckle in a fire as fast and as severely as other materials would. It is important to know that at 30 minutes of fire exposure, only around ¾ inch of glulam is reported to be subject to damage, as compared to a steel structure, which would have collapsed under the same circumstances.

High ambiance quality

Homeowners who make use of glulam structures can enjoy a warmer feel in winter, cooler feel in summer, which is generally a characteristic of tropical hardwoods. Some contractors would recommend glulam members in case of improving and/or overcoming acoustic issues.

The drying technique used on glulam makes it possible to make it dry to extremely low timber moisture. More specifically, glulam beams have a typical moisture content of about 12% at production stage. You can compare this figure with regular green lumber and kiln-dried lumber, the moisture content of which is respectively around 20-50%, and 12%. Thus, glulam can absorb moisture from the surrounding air, without cracking as a result. Homeowners in tropical humid climate should seriously consider this material.

An advantageous and cost-effective application

Not only does glulam have exceptional strength, it also takes much less time to rework and fabricate onsite, which means budget will be scaled down and time saved over the length of the project.

On the grounds that glulam is an engineered wood product, the technology behind it has made it easier for installers to cut, nail, drill, and so on, whereas solid wood products might require certain sets of skills and specific tools to work with. Special machinery is not required when installing glulam. Overall, these particular traits increase the building velocity and decrease the amount of needed effort for glulam structures.

Adhesives for glulam products

Dry service and wet service conditions are two important factors which should be considered by homeowners, same as the producers of laminating adhesives used for glulam–. Dry service requires the member to possess a moisture content of below 16% in service, while wet service requires the number to be at or above 16% in service.

Various glue types are available for glulam usage. One of the most commonly known ones is modified melamine-resin, the line colour of which is light to brown. Other popular kinds are phenol-resorcinal-resin of dark brown, and polyurethane of light to transparent colour. All these adhesives can be used for indoor and outdoor application areas. Modified melamine-resin and phenol-resorcinal-resin adhesives both contain formaldehyde, while polyurethane adhesives do not. However, because formaldehyde is a natural element of wood, you may find a small amount of this substance in polyurethane-glued glulam.

Maintenance techniques

In spite of the fact that glulam is dimensionally stable thanks to its laminated nature, maintenance considerations are still needed. Applying a protective coating will work to limit the effect of weathering on the material which allows it to provide excellent long-term service. Coating procedure should be applied according to manufacturer's instructions. Make sure to repair joint and capping details periodically.

Recap on the qualities of glulam:

1. Long history of popularity and effectiveness

2. Renewable, environmentally friendly source

3. Aesthetically attractive presentation

3. Exceptional fire resistance and chemical resistance

4. Economical, time-saving, versatile application