Mass timber is reshaping the way we build. As the construction industry seeks more climate-friendly solutions, cross-laminated timber (CLT) has emerged as a sustainable and cost-efficient material. In every CLT element, the adhesive plays a crucial role in bonding the wood layers together. Finnish manufacturer HOISKO CLT relies on Kiilto Pro SW 13 adhesive to keep production efficient and ensure lasting strength.
Structural durability begins with the right adhesive
HOISKO CLT manufactures cross-laminated timber elements used in various types of buildings, ranging from schools and libraries to sports centers and private homes. The company also delivers CLT elements for bridges and other demanding infrastructure projects.
“We have decades of experience in timber construction, so we know how wood behaves and what kind of quality our customers expect. We act as a strategic partner for construction companies, not just as an element supplier,” says Jukka Peltokangas, Development Director at HOISKO CLT.
CLT is the most advanced form of modern wood construction. Its cross-layered structure provides strength comparable to steel, allowing it to be used as a load-bearing material in walls, floors and roofs.
The bonding process plays a key role in CLT production, ensuring the structural performance of each element. The adhesive joint must withstand time, mechanical stress and temperature variations, while meeting strict quality standards.
Production is carefully monitored. For load-bearing structures, both the adhesive and the final product require third-party validation.
“Our production is audited twice a year, and we regularly carry out our own shear strength tests on bonded products,” says Markku Herrala, Production Manager at HOISKO CLT.
“You have to be able to rely on your adhesive. A good adhesive is one you don’t need to think about – it works the same way every time.”
One adhesive for the entire production
In CLT production, the adhesive’s open and pressing times depend on the number of layers in the element. In the past, HOISKO used two separate adhesives with varying open times for each element type.
When Kiilto introduced a new adhesive for CLT production in early 2025, the choice was an easy one.
“We’ve been running tests and collaborating with Kiilto for a long time. Now everything fell into place. We found a solution that fits our production perfectly,” Herrala says.
Kiilto Pro SW 13 is a one-component polyurethane adhesive with an optimised balance between open time and pressing time. This allows the same product to be used for all element types manufactured by HOISKO, whether they consist of three, five or seven layers.
“Using one adhesive simplifies production and brings clarity to everyday work. We no longer need to keep track of which adhesive is in stock or running low, since the same solution works for everything,” Herrala says.
Switching to the new adhesive was effortless and didn’t require any changes to the equipment. The press settings were fine-tuned slightly, but production continued without downtime.
HOISKO’s CLT elements bonded with Kiilto adhesive have already been delivered to major Finnish construction projects. These include the new Turku Music Hall and the Elmo Swimming Hall in Vantaa, one of the largest pool projects in the country.
A reliable adhesive keeps production running
Kiilto Pro SW 13 has been designed to speed up production in the wood industry and deliver high strength in demanding applications. The adhesive spreads evenly and penetrates effectively into the wood cells during pressing, ensuring structural durability and high bond strength.
Its viscosity changes with movement, which allows it to be pumped at lower pressures. The adhesive squeeze-out dries thoroughly and doesn’t leave any residue on the machining blades used in the next processing steps. This reduces the need for blade changes and extends their service life.
“Good spreadability, resistance to temperature changes and reliable deliveries are very important to us. Even small details have a direct impact on production efficiency,” the HOISKO team notes.
Long-lasting structures and partnerships
HOISKO’s approach to construction is built around durability – and the same applies to partnerships.
“Collaboration with both our timber and adhesive suppliers is key to keeping everything running smoothly,” Herrala says.
Sustainability is equally important. HOISKO’s customers are increasingly asking about adhesive composition, emissions and safety. Kiilto’s trusted brand and certified low-emission adhesives support the customers’ sustainability goals.
Co-developing adhesive solutions for future needs
In a manufacturing environment, bonding-related questions often arise unexpectedly, and quick support is essential. According to HOISKO, Kiilto’s technical service has always been available when needed.
“What I value most in Kiilto is that they listen and take our feedback seriously. Their expertise is something we can always rely on,” says Peltokangas.
Tailoring customer-specific adhesive solutions is a natural part of Kiilto’s R&D work. One example is a custom edge adhesive developed specifically for Hoisko’s production needs. The special adhesive is used for bonding the edges of the raw material.
“New solutions are continuously developed together as fresh ideas emerge. Our next goal is to meet upcoming fire resistance and energy efficiency requirements in construction,” says Juha Rinne, Business Development Manager at Kiilto.
Every customer test run also provides valuable insights for everyone involved.
“For us, each pilot run at a customer’s site is a learning opportunity. We see how the product performs under real conditions and what we can still improve. Even if the adhesive is the same, every customer’s equipment and process setups are different,” adds Kiilto’s Area Manager Erkki Kivimäki.
“Both parties learn something new – that’s what collaboration is all about,” the HOISKO team concludes.