18 as described below in a preferred embodiment the curb 12 further includes an upper flange 66 extending upwardly from a central portion of the inner flange 56 and a screen support lip 68 extending inwardly along the upper edge of the upper flange 56 together the inner flange 56 upper flange 66 and screen support lip 68 cooperate to define a channel 74 for receiving a screen assembly as noted above the skylight 10 further includes a glass panel assembly 14 the glass panel assembly 14 is preferably a conventional insulating glass having a spacer frame 80 sandwiched between a pair of spaced apart 1 8 inch high strength glass panels 82a b the panel assembly 14 is dimensioned to fit upon the top wall 34 of the curb 12 where it is secured by the retainer 16 as described below alternatively the glass panel assembly 14 can be replaced by a variety of other glazing materials such plastic or other transparent or translucent materials as perhaps best illustrated in fig3 the glass panel assembly 14 is secured to the curb 12 by retainer 16 in a preferred embodiment retainer 16 is manufactured from an extruded elongated l shaped profile of aluminum having top and side walls 76 and 78 individual retainer members 16a d are mitre cut and welded to form a peripheral frame the top wall 76 of the retainer extends inwardly and includes a downwardly extending ridge 81 along its inner edge to engage the glass panel assembly 14 a plurality of mounting holes 83 see fig2.