Always measure the CURB not the skylight frame. DĀLYTE adds 5/8” standard clearance on all sides. The 5/8” clearance is in addition to the curb dimensions provided. Outside curb dimensions should be taken on the exposed curb if possible. The 5/8” clearance is for the roofing materials, flashing and out-of-square curbs. For a detailed drawing of these instructions, please visit our Resources page.