Construction solid wood is lumber made from finger-jointed softwood, which can be used for both visible and non-visible applications. Each piece of construction solid wood (CSW) is fixed at both ends using special clamping devices on a tensile testing machine and then subjected to precisely defined tensile forces. Therefore, tested CSW is safer than solid timber. In addition, compression cracks, fall damages, and other wood defects that were previously undetected with conventional sorting methods can now be identified, and the affected pieces can be eliminated.