Compared to solid masonry or concrete walls, drywall systems enable flexible, rapid and resource-conserving room partitioning. However, conventional systems are based predominantly on finite, energy-intensive raw materials such as steel, gypsum and cement. This results in the generation of high transportation and CO₂ emissions.

Drywalls in timber-frame construction made from the renewable raw material wood are a sustainable alternative, in particular when regionally available species of wood are utilized. Through the application of non-combustible plywood panels as cladding, the requirements for “highly fire-retardant” components in accordance with the 2002 model building regulations can be fulfilled. As a result, non-combustible plywood panels can be used as a substitute for conventional plasterboard or fiber-cement panels for cladding.

“For the project, plywood panels were modified in such a way that they can be used as a non-combustible construction material for building construction in accordance with the German standard DIN 4102-1. Although a classification in accordance with DIN EN 13501-1 in class A2 was originally planned, this proved to be unfeasible. With the completion of the project, it is now possible to implement drywall constructions in areas with heightened fire-protection requirements through the use of specially developed plywood panels instead of gypsum fiberboard or plasterboard,” reported Dr. Torsten Kolb, Project Manager at the Fraunhofer WKI.

The research partners first drew up a catalog of requirements for a non-combustible plywood panel and a suitable, highly fire-retardant wall structure. On this basis, the project partners then developed new types of plywood, which were comprehensively characterized by the Fraunhofer WKI in terms of thermal stability, emissions (including VOC), odor and mechanical properties.

As the DIN EN 13501-1 standard distinguishes between inhomogeneous and homogeneous construction materials and the plywood is considered inhomogeneous, all components (veneers and adhesive) must be tested individually. For this reason, the European construction-material class A2 in accordance with DIN EN 13501-1 could not be achieved, and the fire-protection classification was performed in accordance with DIN 4102-1, which is valid in Germany. A highly fire-retardant drywall structure was subsequently successfully transferred from the small format (50 × 50 cm²) to the large standard size (3 × 3 m²) and subjected to testing.

The newly developed, non-combustible plywood panel and its incorporation into a highly fire-retardant drywall extend the application and design possibilities of wood in interior construction and interior design — without thereby neglecting stricter fire-protection requirements. Potential users include, in particular, companies in the wood and wood-based materials industry (including forestry suppliers), the drywall industry, property developers and (interior) architectural studios, the joinery trade and the furniture industry.