A new building system that slides cross-laminated timber ceiling and wall panels into a reinforced concrete floor and frame could be the next big thing in offsite construction – with the system having the potential to shake up low-rise residential and commercial construction.
Dubbed the “Eco-Box,” German-based Züblin, a subsidiary of Austrian firm Strabag, is behind the concept; with the support of the German Federal Ministry of Food and Agriculture, is now working with the University of Applied Sciences in Stuttgart to develop a new prototype.
The project, now subject to a 36-month demonstrator programme, will see a “timber construction system developed to combine a modular design with a decoupled, primary load-bearing system.”
“The demonstrator will be used to research and implement information on prefabrication and logistics, BIM, building physics investigations and sustainable building service technologies in five work packages,” said Züblin, who spoke to Construction Briefing about the project yesterday.
Ultimately, “the developing method is meant to deliver a new product while analysing sustainability gains,” the firm said, adding that the “(Eco-Box) should allow for architectural diversity and variability, taking into account the location factors as well as the building’s internal structure.”
Eco-Box slides cross-laminated timber into place like a drawer
According to Züblin, the system differs from traditional prefabrication modules, with the mass timber units sliding into a primary structure rather than individual units stacked on top of each other: “Eco-Box is based on the modular principle, which consists of separating the modular system into a primary and a secondary supporting structure.”
In other words, the CLT modular units are placed and fixed to a primary supporting structure rather than the units themselves serving as primary supports: “This construction method means that special uses [like] double storeys can be realised easily and cost-effectively.”
“The primary supporting structure forms a frame of reinforced concrete, [along with] the secondary supporting structure (the so-called ‘Eco-Boxes’). These are not stacked on top of each other but pushed into a stiffened shelving system like drawers. (In addition), boxes can be used individually for small apartments or combined for larger residential or office units.”
A representative from Züblin discussing the Eco-Box concept.
Is the Eco-Box process more sustainable?
Although the Eco-Box is still in the prototype phase, Züblin believes it has seen early positive returns on sustainability goals, particularly the reduced time and materials needed to produce an Eco-Box project. For now, however, the team is ironing out key issues – relating to noise and moisture protection.
“We see the development of optimal, recyclable design solutions in combination with a recyclable overall process, from production and construction to operation and dismantling, as the greatest challenges,” said Züblin, who added that “issues relating to noise and moisture protection are the top priority.”
The company also said that a persistently soft builders market is a hindrance “due to the almost complete standstill of the residential construction market.”
But if builders can get back on the job, Eco-Box could be a key driver in meeting German construction goals:
“When using wood, a high degree of prefabrication can be achieved with great manufacturing accuracy. In addition, the transport weights are still easy to handle. Furthermore, once the research work has been completed, the system should be recyclable, [and] the materials should be almost completely recyclable by type.”
- Click here to learn more about the role of engineered wood products, like cross-laminated timber, in reducing the world’s dependency on concrete-based construction.
