Cross-laminated timber could be low-carbon building material of the future

Cross-laminated timber could be low-carbon building material of the future

As more construction firms look to reduce their carbon footprint by sourcing alternative, low-carbon building materials, Europe’s largest forest-based products company Stora Enso has stepped up investment in its very sustainable cross-laminated timber (CLT) products. Many companies view CLT solutions as the ideal replacement for carbon-intensive concrete and steel structures.

The CLT market has already grown threefold in the past two years and the company has announced a new €45m investment into a production line development that will make it the biggest supplier of CLT globally. The investment will boost Stora Enso’s volume capacity, adding 100 km3 annually.

The investment looks set to transform the packaging firm into a renewable materials company and the largest global producer of a low environmental impact timber solution which can replace steel and concrete in construction projects. 

CLT is produced from softwood timber and consists of sections that are laid across each other at right angles. This allows the panels to be designed to specific dimensions for items such as windows, doors, and plumbing, ventilation and wiring openings.

The main benefit of CLT is its lower embodied carbon footprint and quick construction time compared to traditional methods. Some projects can be completed six times faster than a standard build because of the panel construction process. The layered design process strengthens each panel or plank, making it a suitable substitute for steel or concrete. Stora Enso  products are cost-effective and do not disrupt certified sourcing practices and a zero-waste ethos at its mills.

Figures suggest that around one-third of all landfill waste comes from the construction sites, either from construction or demolition of a building. CLT is an offsite solution and modular aspects of buildings can be constructed at CLT mills if specified. As recycling is easier to implement in a factory environment, the widescale use of CLT could improve landfill rates from the construction sector.

CLT is also much lighter than traditional building products, which allows for reduced slab and improves the embodied carbon of a project as a result. CLT panels are also better insulators, reducing heating and insulation costs.

CLT_product_2000x884

Stora Enso has two production plants in Austria that support the production of the engineered wooden structural materials and the Nordic region is a strategic location for Stora Enso, as it provides easy delivery routes to the UK and Scandinavian nations – countries that are leading the charge in sustainable construction. It is one of the only European companies to offer both CLT and laminated veneer lumber (LVL) solutions for construction firms. It 

The new €45m investment will introduce a new CLT production line in Sweden, at Stora Enso’s Gruvön Mill. Production is scheduled for 2019 and will add extra capacity to the Gruvön saw mill, rather than replacing it. The new CLT production line will run alongside current operations at the saw mill, providing a cost-effective solution to increase supply to the market.

Stora Enso expects two-thirds of energy consumption at its mills to come from biomass derived from burning wood bark The company has a strict sourcing policy to ensure that all packaging products are made from Forest Stewardship Council (FSC) or Programme for the Endorsement of Forest Certification (PEFC) certified timber from nearby forests.

Any sawdust generated onsite will also be used for wood pellet production, while bark from the timber is used in bioenergy production at a dedicated combined heat and power (CHP) system in Austria. Overall, Stora Enso expects two-thirds of energy consumption at its mills to come from biomass derived from burning wood bark.

Stora Enso has a pre-existing policy of replanting trees for each one harvested, and this will be continued as part of the CLT expansion. The number of plants per hectare varies according to tree species and place of growth, but there are always more trees planted than harvested. CLT is made of spruce and this regeneration process will require approximately 2,000 plants per hectare.

Users of CLT argue that the replanting of trees with saplings actually reverses the emissions from the harvesting process to create a negative CO2 balance.

Further information