Lignotrend Sawmill Relies on KNAPP Connectors
The EVO-GRIP connector enables reliable connections between main and secondary beams and columns for medium to extremely high loads (55 kN to 550 kN). This adjustable heavy-duty connector consists of two identical plates made of high-strength aluminum, featuring a ribbed backside for enhanced grip.
Quick connections for cross-laminated timber – designed to eliminate cross-pressure
The Lignotrend sawmill in Ibach is one of the few facilities capable of processing large-diameter timber of up to 1.40 m. To increase production capacity from 10,000 to 25,000 solid cubic meters, the existing sawmill was expanded and upgraded.
For this project, the KNAPP EVO-GRIP connector was introduced as an efficient solution for demanding ceiling-to-wall connections. To widen the sawmill hall, the gable roof was extended on the eaves side and complemented by a flat roof structure. Due to the limited room height, the cross-laminated timber (CLT) elements had to be connected directly to the existing gable roof trusses—requiring a compact yet high-performance connection solution.
In close collaboration with Lignotrend, KNAPP developed the EVO-GRIP for this application—a two-part connector with adjustable width. This flexible system enables both classic beam connections (from 60 mm connector width) and wide ceiling-to-wall applications using a single profile cross-section. A key feature is the ribbed backside, which presses into the timber via 45° screw connections. This significantly increases friction and enhances load-bearing capacity. The standard EVO-GRIP—typically available in two versions, Standard and Solo—was used here as a customized solution adapted by KNAPP Verbinder to the project’s specific requirements: Gigant Grip Profile H = 200 mm.
The EVO-GRIP connector also allows horizontal displacement perpendicular to the element’s tension direction within the tongue-and-groove joint, ensuring a stress-free and durable connection.
The connector rail allows Lignotrend CLT elements to be slid laterally into the tongue-and-groove joint—enabling fast and precise installation.
Ideal for demanding construction details with continuous walls, such as elevator shafts or multi-story buildings where floors meet continuous CLT walls.
Installation
The installation process was designed for efficiency and precision. One part of the connector was mounted onto the sides of the gable trusses, while the second part was fixed to the ends of the CLT panels. A projection of approximately 2 cm on the top of the panels served as a positioning aid during installation. Pre-assembled connectors reduced on-site effort and ensured a smooth workflow. The elements were lifted into place using a lifting platform and connected quickly and securely. Graphite strips were additionally installed between the panels as a fire protection measure.
The connector rail enables CLT elements to be slid laterally into the tongue-and-groove joint—significantly simplifying connections in multi-story buildings compared to conventional methods.
Pre-assembled connectors allow for fast and efficient installation directly on site.
Advantages
The selected solution delivers clear benefits in both planning and execution:
“The straightforward CLT detail simplified the framing process. Installation was faster, easier, and required no scaffolding. Once installed, the suspended connector also prevents potential lateral compression,” explains Alexander Villinger.
Lignotrend now plans to use the EVO-GRIP profile more frequently in future projects:
“With the connector rail, we can slide our CLT elements laterally into the tongue-and-groove joint,” says the project manager and graduate engineer in timber construction (FH), responsible for the sawmill expansion.
“This is especially valuable for complex construction details involving continuous walls—such as elevator shafts or multi-story buildings. Previously, these connections required notching and conventional supports. The EVO-GRIP connector significantly simplifies this process.”
The first part of the connector was mounted on the sides of the gable roof trusses.
The second part of the connector was attached to the end faces of the cross-laminated timber (CLT) elements during prefabrication.
Project Data
- Project: Sawmill Hall Expansion
- Project Details: Extension of an existing production facility
- Construction Method: Timber post-and-beam structure with CLT roof elements
- Connection System / Product: EVO-GRIP™
- Client: LIGNOTREND Produktions GmbH & Co. KG
- Architect: RHEINER & VILLINGER Consulting Engineers
- Structural Engineer: Alexander Villinger
- Timber Construction: Holzbau Amann GmbH
- Year of Construction: 2024
- Gross Volume / Area: 21,000 m³ / 2,200 m²
- Address: Zur Säge 2, 79837 Ibach, Germany
Photos: LIGNOTREND / © Granacher, Weilheim; KNAPP® GmbH
