A timber wall frame for use in building construction has an opening for a door or window defined at each side by a vertically extending prop stud and jamb stud in side by side relation, and the opening is defined from above by a horizontally extending top plate of the wall frame. The prop stud and jamb stud are of the same length and extend to the underside of the top plate. A lintel of sheet metal spans the upper side of the opening, the lintel having a vertical wall and a horizontal flange along the upper edge of the wall. The lintel is applied to the frame so that its vertical wall overlies a face of each stud and a face of the top plate, with the horizontal flange of the lintel being above the top plate.