the pressing means as seen in fig6 the isosceles joist of the present embodiment shows a transverse sectional view of a multitude of the isosceles joists each half joist 56 comprises a top and bottom elongated wooden flange member 20 of rectangular cross section and longitudinal grain structure interjected by a plywood web member 22 flange members 20 may be made exemplarily from nominal size structural grade lumber or laminated wood products and the web member 22 may be made of a minimum of a three ply laminated wood product is joined to flange member 20 by a continuous adhesive joint 23 along the diagonal of the flange member 20 referring to fig7 the isosceles joist of the present embodiment shows a transverse sectional view of a multitude of the isosceles joists which form purlins for the attachment of a structural metal roofing system 44 each half joist 56 comprises a top and bottom elongated wooden flange member 20 of rectangular cross section and longitudinal grain structure interjected by a plywood web member 22 flange members 20 may be made exemplarily from nominal size structural grade lumber or laminated wood products and the web member 22 may be made of a minimum of a three ply laminated wood product is joined to flange member 20 by a continuous adhesive joint 23 along the diagonal of the flange.