The effect of moisture content on mechanical properties of corner furniture joints was evaluated for when different joining methods and materials were used. Results included statistical processing of the measured and calculated data and evaluation of the effect of selected factors on mechanical properties of joints caused by using mechanical fasteners and glue. The load-carrying capacity and stiffness of corner joints were investigated in two environments, humid and dry, with standard conditions for temperature and pressure, i.e., dry environment had a temperature of 23 °C ± 2 °C and relative humidity of 45% ± 5%, and the humid environment had a temperature of 23 °C ± 2 °C and relative humidity of 90% ± 5%. The two types of materials used were particleboard (PB) with a thickness of 12 mm and artificial stone (plastic) with a thickness of 12 mm. Both materials were tested individually as well as their combination. Epoxy and polyurethane (PUR) adhesives were used for the glued dowel joints. When the same materials were bonded, maximum load carrying capacity was achieved with PUR adhesive, material combination of plastic-plastic, and moisture content of 90%. The epoxy adhesive was most suitable for bonding materials with different properties.

With their properties, upholstery covering materials significantly influence the quality of upholstered products. These materials form the surface layer of upholstered furniture; any damage to this material is immediately visible to the user. We consider the stitches connecting the covering fabrics to be one of the critical points of the upholstered surface, therefore they must have the required strength. Faux leather is one of the most used upholstery materials. The main aim of the paper is to determine the effect of upholstery faux leather, stitch length, point needle, and needle size on the strength of the stitches and the seam efficiency. The results of the experiment proved the suitability of using a sewing needle LR for joining covering materials such as faux leathers. The highest force to seam a rupture in the joints was achieved in the direction of the warp yarns of the underlying layer of PU (Polyurethane) faux leather with a stitch length of 4 mm and needle type LR/90. The highest seam efficiency was achieved with seams in the direction of the weft yarns of the PVC (Polyvinyl chloride) faux leather underlying layer with a stitch length of 4 mm and needle type LR/90. If the underlying layer of faux leather is a fabric with canvas binding, a higher seam efficiency of joints is assumed.