The limited deformation capacity of wood-based materials restricts their application in creating double-curved structures. To achieve single-layer double-curved structures, permanent plastic deformations are necessary to fix the deformation. To capture the complex deformation behavior of a double-curved structure in a realizable test setup, tensile tests based on strain measurement were conducted. This study investigates how steaming and subsequent drying affect deformation behavior of cut-out patterned high-density fiberboards (HDF). A lattice auxetic cut-out pattern was applied to 3 mm Fundermax Biofiber panels. Results indicate that steaming increases the residual strain, with 65–70% of the strain remaining after 24 h of recovery. The residual strain was confirmed after 14 days. Drying under load further enhances this residual strain, converting up to 90% of the strain into a residual plastic state. In contrast, dry samples exhibited primarily elastic strain, with no residual strain. The findings demonstrate that steaming and controlled drying under load can fix the deformation, enabling the production of single-layer double-curved panels.