Unedged board 25, 30, 40, 50mm thick, uncalibrated (different) in width and with bark on both sides is widely used for the construction of both private and industrial facilities. It is thanks to its physical and mechanical properties that wood is widely popular for use both for load-bearing and auxiliary structures of buildings and structures. Buying a high-quality pine board or buying a high-quality pine mounting rail is the key to successful construction. It is especially worth paying attention to the fact that the material is pest-free (without sawdust) and free from fungal damage (without blue stain). Also extremely important is the issue of observing the geometry of the lumber, which greatly affects the possibility of its further installation and operation. Depending on the cross-section of the lumber itself, its transverse dimensions must be within the range of 1mm - 3mm in size deviation from the declared ones, which is regulated by standards and is called "tolerances of deviations in the dimensions of transverse cross-section". Also, lumber must be within tolerances in longitudinal dimensions, which is also regulated by building codes (propeller run) and has a strong impact on the further use of lumber. Therefore, before buying lumber, be sure to pay attention to the above information, and do not be guided by the rule that finding "cheap" lumber means saving. Usually it is cheap precisely for the above reasons: non-compliance with dimensions, longitudinal curvature and the presence of sawdust and fungal impressions. We wish you the right choice of lumber and successful construction.