Panel for the construction of containment walls of formwork for concrete pouring, in particular for containment formwork for the construction of concrete slabs or the like, which panel comprises at least one wooden plate or one plate comprising wood, which wooden plate or which plate comprising wood is coated in at least some areas, preferably on their outer faces and/or along the edges with a waterproofing and/or protective coating and wherein the wooden plate or the plate comprising wood is formed of at least one layer of birch wood which is arranged in relation to the longitudinal and width directions of the panel with the wood fibers in a first direction and at least one layer of fir wood which is arranged in relation to the longitudinal and width directions of the panel with the wood fibers in a second direction, said two wooden layers being coupled together by means of chemical/physical adhesion along the faces of mutual contact and the said first and said second direction can be parallel or not parallel to each other and wherein said panel has in one or more points of one extension of the faces of the panel, at least one engagement seat in the form of a hole, being provided in combination with each hole a corresponding locking pin having a stem threaded externally and the diameter of the hole and the diameter of the corresponding pin and of the external thread of the stem being commensurate with each other in such a way as to tighten the said pin in said hole by screwing, while said pin has at one end of the threaded stem , a head which is radially enlarged with respect to the threaded stem and/or to the engagement hole in the panel, and said hole is at least partially provided with an internal thread corresponding to the external one of the pin or the thread of the pin is of the self-tapping type, that is, which notches upon screwing the internal thread in the walls of the hole, the diameter of the said hole being commensurate with the minor diameter of the external thread of the pin and the diameter of the threaded stem of said pin is approximately 20mm, while the depth of penetration of the same into the panel is approximately 15mm and the thickness of the panel is greater than said depth of penetration. wherein said panel has in one or more points of one extension of the faces of the panel, at least one engagement seat in the form of a hole, being provided in combination with each hole a corresponding locking pin having a stem threaded externally and the diameter of the hole and the diameter of the corresponding pin and of the external thread of the stem being commensurate with each other in such a way as to tighten the said pin in said hole by screwing, while said pin has at one end of the threaded stem , a head which is radially enlarged with respect to the threaded stem and/or to the engagement hole in the panel, and said hole is at least partially provided with an internal thread corresponding to the external one of the pin or the thread of the pin is of the self-tapping type, that is, which notches upon screwing the internal thread in the walls of the hole, the diameter of the said hole being commensurate with the minor diameter of the external thread of the pin and the diameter of the threaded stem of said pin is approximately 20mm, while the depth of penetration of the same into the panel is approximately 15mm and the thickness of the panel is greater than said depth of penetration. <EOS>