Abstract: A seat plate for protecting wooden structural members against structural damage due to crushing, as well as the effects of moisture, humidity and the like. The plate member includes a pair of mutually perpendicular planar members and, in one embodiment, is in the form of a flat sheet metal plate which is bent along a fold line to provide first and second planar plate portions intersecting each other at right angles. One of the plate portions has a dimension in a direction perpendicular to the fold line which is substantially greater than the dimension of the other plate portion in a direction perpendicular to the fold line. The smaller of the two plate portions has a plurality of teeth struck therein to provide a means of attaching the seat plate member to the wooden structural member.