The project, funded by the German Federal Ministry of Food and Agriculture (BMEL) through the Fachagentur Nachwachsende Rohstoffe e.V. (FNR), aimed to create a novel, environmentally friendly process that enhances the weather resistance, dimensional stability and durability of wood‑based substrates used in outdoor applications such as façade panels and playground equipment. The strategy combined two complementary approaches: first, the development of thermally modified wood‑based substrates (mHBS) derived from fast‑growing, locally sourced hardwoods, and second, the application of a powder‑based coating system that is solvent‑free and low in volatile organic compounds.

In the initial phase, a range of candidate woods—birch, poplar, beech, and spruce—were selected and subjected to a compression and thermal treatment protocol. The process parameters were tuned to achieve a homogeneous density profile while minimizing post‑processing shrinkage and swelling. Adhesives such as phenol resin, PVAC 2K, and PUR 1K were evaluated for lamination, with the requirement that they not interfere with subsequent coating adhesion. The resulting mHBS panels exhibited a density increase of up to 20 % compared with untreated wood, and porosity was reduced by roughly 30 %, leading to a measurable improvement in mechanical stiffness. Tensile and flexural tests confirmed that the strength of the mHBS correlated strongly with the achieved density, meeting the target specifications for outdoor structural use.

Parallel to substrate development, a suite of 12 liquid coatings and three powder coatings (both nitrocellulose and UV‑curable) were screened for compatibility with the reference substrates. The powder coatings were applied in a two‑step process: first, an ion‑based primer (ionFl) was sprayed onto the substrate surface, followed by the powder layer. Optimization of spray parameters—distance, pressure, and drying time—resulted in a primer that reduced fiber swelling by up to 15 % and improved long‑term adhesion. Subsequent coating trials on the mHBS panels demonstrated that the powder system achieved a uniform film thickness of 120 µm and a hardness of 80 HRB, while maintaining a low coefficient of friction suitable for outdoor use. Accelerated weathering tests (UV exposure, salt spray, and freeze‑thaw cycles) showed that the coated mHBS retained over 90 % of its initial gloss and exhibited no delamination after 12 months, indicating superior durability.

The project’s technical milestones were met on schedule. Work package 1 (March–May 2019) completed material selection and preliminary coating trials. Work package 2 (May–September 2019) produced reference substrates and established baseline mechanical and coating performance data. Work package 3 (June–October 2019) refined the thermal‑compression process, achieving the desired density and dimensional stability. Work package 4 (July–November 2019) optimized the ionFl primer application, while work package 5 (November 2019–August 2020) finalized the production of mHBS panels from poplar and birch. Subsequent work packages focused on powder coating application, material characterization, and techno‑economic assessment, culminating in a comprehensive evaluation of the system’s feasibility for commercial deployment.

Collaboration involved a consortium of research institutions and industry partners. The research arm, comprising university laboratories specializing in wood science and materials engineering, conducted the experimental work and data analysis. Industrial partners supplied pilot‑scale equipment, performed field‑level trials, and provided feedback on manufacturability and market requirements. The consortium operated under a coordinated project schedule, with regular progress meetings and shared data repositories. Despite pandemic‑related personnel shortages and supply chain disruptions, the partners successfully carried out additional industrial trials that validated laboratory findings. The project concluded with a final report submitted to the BMEL in April 2023, documenting the scientific advances, performance metrics, and a roadmap for scaling the technology to commercial production.