#glulam

Composites: Glued laminated timber

Glued laminated timber, also known as glulam, is a composite material made from wood and adhesives. Laminated wood is bonded together with moisture resistant adhesives and can take the form of simple, straight beams or curved structures. Several types of wood can be used to create glulam (often pines, cedars, or firs, and sometimes a mixture of several types) and different woods have to be treated differently to create the finished product. Currently, resin glues are the most common adhesives used.

A form of engineered wood, glulam is sometimes divided into different categories. Laminated veneer lumber, parallel strand lumber, and laminated strand lumber are sometimes interchangeable but have slightly different properties and applications.

On a pound for pound basis, glulam is stronger than steel with a greater compressive strength than concrete, and overall lighter than both of these materials. It is also stronger and stiffer than similar sized, non-glulam timber. Glulam can also be manufactured in a wide variety of shapes and structures, allowing for unique finished products. It's main disadvantage is the glulam is much more expensive than regular timber, but for higher-strength applications the cost is typically considered to be worth it. Glulam's properties also, of course, depend on the quality of the adhesive used.

Mostly used in architectural applications, glulam is utilized in structures as varied as vaulted ceilings, flat roofs, complex arches, bridges, or simple floor beams. Sometimes applications take advantage of the beauty wood structures can convey, others simply utilize glulam for its strength. The world's tallest wooden structure is an 18 story building in Norway and category 5 hurricane-resistant log houses are constructed from this material.

Wondering about the formaldehyde content of this stuff.

Given my (admittedly limited) understanding of the topic, adhesives used in glulam are moisture resistant and therefore formaldehyde emissions are low and well within the levels consider safe (i.e. the formaldehyde does not separate from the other parts of the adhesives because of the water resistant nature of the adhesives as a whole). (Here’s a source.)

However, there are a variety of adhesives used in glulam products and yes, some of them contain formaldehyde. (Have another source.)