“CLT has opportunities for significant advantages over steel, concrete or masonry construction in terms of environmental credentials, speed, weight, and structure as finish” – Alex de Rijke, dRMM
We previously asked the question “Is the Construction Industry About to Enter a Timber Age?” As architects and designers make the switch to building with Cross-Laminated Timber (even going as far to refer to it as the “Concrete of the 21st Century”) it’s become clear that the Timber Age isn’t about to begin, it has already begun.
Designers are embracing this new material for projects throughout the world. Hawkins/Browns of London combined CLT and steel to produce “the Cube,” a 33-meter high apartment block in London they claim is “the tallest building to use structural cross-laminated timber in Europe.” Beyond that they’ve produced CLT recital halls and tree-houses as well as using Cross-Laminated Timber to modify office and educational space. Lever Architecture of Portland proposed and designed Framework, a prize-winning mixed-use building that, if constructed, will be among the largest wooden buildings in the United States. Further structures can be found in Chicago, Finland, and Canada to name a couple of ever-growing examples.
This mass-adoption of Cross-Laminated Timber comes as no surprise when you list out the benefits it provides.
What are the Benefits of Cross-Laminated Timber?
Put simply, Cross-Laminated Timber is a prefabricated panel made up of kiln-dried wooden boards stacked in alternating directions (where the cross of the name comes from), then stuck together with structural adhesives. These panels are prepared with CNC equipment, allowing for precise specification and application in construction.
Most, if not all of CLT’s benefits stem from this design and preparation.
Simple, Quick Construction
Cross-Laminated Timber panels are lightweight and arrive on site with a structural system ready to be assembled. The process is both simple and swift, allowing for immediate and accurate construction which in turn saves time and money. CNC-prepared panels also allow for greater creative control when designing and building structures.
In Japan, a seven-story CLT building’s durability in an earthquake scenario was tested through fourteen shake-tests and came out with minimal damage. Airtight construction of each panel and precision fitting through CNC preparation leads to seismic resilience, as does its unique strength-to-weight ratio.
Though it may sound strange to tout fire-resistance as a benefit of a wooden building material, it’s one of Cross-Laminated Timber’s greatest strengths. The lamination of CLT has an inherent fire-resistance to it, and the construction of the panels and structures allows little room for fire to breath and expand.
Additionally, the solid thermal mass of CLT prevents the conduction of heat from one side of the panel to the other, allowing extremely high temperatures to remain isolated to a side as the other remains at room temperature.
The nature of wood makes it the only building material that can be regrown and feasible in the long-term. Precision cutting of CLT minimizes on-site waste and its manufacturing requires less energy than producing steel or concrete. Cross-Laminated Timber’s light carbon footprint is one of its greatest strengths.
Solid wood paneling provides superior acoustic insulation, dampening both airborne and impact noises. Its lightweight nature also leads to quiet construction, making it ideal for urban development.
In the same way that Cross-Laminated Timber’s airtight design creates auditory insulation it also creates thermal insulation. Tightly packed panels can trap 90% of the heat that would ordinarily escape from a home. CLT’s previously-mentioned high thermal mass means that temperatures are kept stable and comfortable.
There’s a warm, soothing visual quality to building with wood that separates it from the lifeless concrete slabs that typically fill a city. Cross-Laminated Timber also grants designers with the freedom to experiment with more organic and creative structures than previously allowed by old-fashioned building techniques.
When comparing the manufacturing costs of certain steels and concrete, as well as the money saved on shorter construction time, CLT comes out as at a competitive price.