Timber and timber products are renewable materials that, due to their durability and strength properties, meet the requirements of the construction industry, are widely used in buildings. An analysis of the scientific literature has shown that there is a lack of detailed research that fully investigates the influence of the rate of increase of the moisture content of the timber on the mechanical and, especially, the strength properties of the LVL panels. Upon immersion into water of the bottom of the specimen, the water starts rising quite quickly at the edge of the specimen, and the first six hours are the most critical. The levels of water rise inside the LVL specimen were less significant than at the edges. It was found that water significantly affects the bending strength of the panels, which, when the strength of the wet panel compared to the strength of the dry panel, decreases to 45% after one soak cycle and almost to 52% after two soak cycles. The tensile strength of the wet specimens is ~40% less than that of the dry specimens. The strength of the panels that were dried back to their initial state was found to be sufficient again, different from the initial strength only within the error limits; the strength properties of the building structure will not be affected.

The research investigated the impact of environmental factors (temperature and humidity) on pine glulam, oak glulam, and laminated veneer lumber (LVL) elements, all of which can be used in building structures. Elements underwent...

Depending upon the conditions in which they are used, wood products are required to have been produced with the necessary moisture levels for the intended job. In many cases, this means that drying is required in order to achieve these moisture level...

In this study, the effect of finishing process on the mechanical properties of oak and pine wood elements were investigated. A special test stand was used for this purpose. Specimens were divided into subgroups, the resonance frequency of the specimens was determined (when they vibrate in mode of a theoretic isotope beam), and the modulus of elasticity (MOE) and damping coefficient were estimated. It was determined that MOE of oak and pine specimens was 8415-10570 MPa and 8220-14104 MPa, respectively, while damping coefficients were 0.014-0.019 r. u. and 0.013-0.026. Afterwards, some specimens were varnished (pentaftal varnish was used), while the specimens from others subgroups were oiled (water-based outdoor wood oil was used) and after each processing step, the viscous elastic properties of the specimen were recorded. The specimens were finished four times – first, one side was finished in two layers, and then the other side. For the determination of elastic properties of the finishing materials, films were prepared separately. The fi lm formation was carried out by casting liquid on a smooth, siliconised surface of a test panel. The tensile test was carried out using the universal testing machine. It was established that MOE of films varied in the range of 4-7 MPa. After the varnishing process, the MOE of oak and pine elements decreased by 5 % and 7 %, respectively, while the damping coefficient decreased (in varnish case) by 60 %. The impact of oil on viscous elastic properties of the specimens was quite marginal.