The innovation and construction industries are spectators who can contribute to waste generation and abuse the use of materials harming the environment. On the other hand, it can promote energy and materials which are renewable, sustainable, and promises a clean outcome. The current situation of our planet’s climatic scenario asks for decisions and technology that are mindful of the environment and its various layers. Timber construction had some reservations due to its effect on deforestation and unsafety. But the recent methodology of wood works has had innovative results that have pushed the boundaries of construction purely out of wood. 

Cross-laminated Timber (CLT) is a construction material that has emerged to be a good wooden product with good potential to be replaced with concrete and steel. It is a category of mass timber where wooden logs are glued together and make a panel. These panels are extremely strong and sturdy; thus, they can be used to build walls, ceilings, floors, and the entire frame of a building. The material has proved to be compelling enough for low-rise and mid-rise typologies. Apart from sturdiness, it has also shown an inclination towards speedy construction, reasonable costs, versatility, and impressive appearance. But the fascinating element of the material is its sustainability abilities. It was initially used in the 1970s in Europe and is made of leftover wood scraps with spruce, pine, and larch. It is manufactured in a factory where lumber is first softened and trimmed. It is then dried in a kiln that reduces the moisture inside. This resists cracking and strengthens the piece. The lumbar planks are then stacked on each other in a perpendicular direction. These layers of planks are called lamellas. (All You Need to Know About Cross Laminated Timber CLT, n.d.) 

Cross Laminated Timber: Eveything to know about - Sheet1
CLT panels_© Flickr

These lamellas are attached with an adhesive that is not environmentally threatening. They are then pressed using hydraulic to be strong and sturdy. At last, coating and sealants are applied on the panels to protect them from decay and moisture. The size of these panels is according to that of its manufacturing machinery. The length of the meetings, however, can vary according to the transportation length. Typically, the width of a panel can be 3.5m, and the length is 13.5m, but it can extend up to 22m. The panels can also be custom-made for the lining of doors and windows. 

Compared to other hardwood materials, CLT is more reliable due to its enhanced mechanical properties. The panels of CLT are fabricated in the factory and then put together on-site, reducing the overall waste during production. The pre-fabrication process also contributes to speeding up the construction process because fewer joineries are needed, giving the overall design some flexibility. CNC machines can also be used to produce these panels. The total energy behind manufacturing the panels is much less than that required to produce steel and concrete products. CLT panels need half of the energy required to make concrete and only one per cent of that required to make steel. Multiple factors like these cut off the overall cost of the construction process and the management, not to mention its minimal impact on the environment due to less pollution, noise, and dust. (All You Need to Know About Cross Laminated Timber CLT, n.d.) 

Cross Laminated Timber: Eveything to know about - Sheet2
A structure out of CLT_©Andrew Giammarco

Wood tends to envelop carbon dioxide within the skin. Thus, CLT panels can benefit people’s health, inhibiting the space it’s used in, for it is a carbon-negative material. 

The cross-grain skin of CLT makes it incredibly strong; thus, it is ideal for structural integrity. It is also comparatively much lighter and shows good strength than steel or concrete. Another impressive element of CLT panels is their tendency to resist fire. During a fire outbreak, the surface of the panels will char, which is like a protective layer to maintain toughness. The char delays spreading the fire, giving the occupants time to evacuate the space. To retain maximum strength, panels are set up and down in the outer layers of the walls for strengthening vertically, while on the roof and floors, the outermost layers are arranged parallel to the most extended span length. CLT panels undergo multiple for earthquake resistance, and the results were impressive. While concrete will form cracks during an earthquake and require replacement, CLT panels can be repaired, and thus replacement can be avoided. The making of CLT, from wood sourcing to transportation, potentially involves employment from rural communities. The rural settlements near the pine or spruce forests can work and generate revenues for their community in the various stages of CLT manufacturing. This can lead to the overall growth and development of the grappling rural communities. (Roberts, 2020)

Cross Laminated Timber: Eveything to know about - Sheet3
Joinery between two penels_© Sauter Timber

Along with floors, roofs, and walls, CLT panels can be used for load-bearing building frames, cantilevered floors, elevator shafts, and balconies. Previously, CLT panels were used for low-rise to mid-rise structures, but with recent technology and advancements in the material, high-rise construction with these panels is seriously considered. The panels are now used for residential, commercial, institutional, and civic buildings. The grain pattern on the panels gives the building a beautiful and sober appearance. It can be set up in its original way and left exposed or it can be cladded if desired in the future. (What Is Cross-Laminated Timber (CLT)? | Naturally: wood, n.d.) 

While experiments are carried out to replace concrete and steel for good, the tallest timber building in the world is currently an extraordinary exception. Mjostarnet is located in Brumunddal, Norway, and was designed by Voll Arkiteckter. The 18 storeys building is 85.5m high, with an area of 15,000 sq. m, and is purely erected out of CLT and glulam. It is a mixed-use typology that houses a restaurant, office spaces, a swimming pool, and apartments. The construction was carried out in five stages, completing four floors at once. The prefabricated panels were laid in sections on floors and walls from a crane and an internal scaffolding within the frame of the building. The wood and labour for the construction were locally sourced. The building has put the small town on the map. The view of the lake and the forests from the building makes it an attractive spot. The urban planning authorities of the city included walkways and cycling tracks from Mjostarnet to the town so that it is easily accessible. (Pintos, 2020)

Timber construction will be in demand in the coming years. With a rapid increase in population and climate change at its peak, it will be vital to turn to a material that doesn’t add fuel to the fire.

Cross Laminated Timber: Eveything to know about - Sheet4
The building of Mjostarnet _©Woodify AS and Vjus AS

References:

All You Need to Know About Cross Laminated Timber CLT. (n.d.). Arch2O. Retrieved December 24, 2022, from https://www.arch2o.com/cross-laminated-timber-clt/

Pintos, P. (2020, February 25). Mjøstårnet The Tower of Lake Mjøsa / Voll Arkitekter. ArchDaily. Retrieved December 24, 2022, from https://www.archdaily.com/934374/mjostarnet-the-tower-of-lake-mjosa-voll-arkitekter

Roberts, D. (2020, January 15). Sustainable building: The hottest new material is, uh, wood. Vox. Retrieved December 24, 2022, from https://www.vox.com/energy-and-environment/2020/1/15/21058051/climate-change-building-materials-mass-timber-cross-laminated-clt

What Is Cross-Laminated Timber (CLT)? | naturally:wood. (n.d.). Naturally Wood. Retrieved December 24, 2022, from https://www.naturallywood.com/products/cross-laminated-timber/

Author

Nishal is a budding architect, exploring and persisting every interest she has acquainted with. She has embraced the profession of architecture as more of a way of life, as how she explores places and meets people. Nishal has a knack for music, photography, and feel-good movies, she hopes to find the sweet balance between her hobbies and her interest which is now her profession.

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