Since 1955, Columbia Manufacturing Co. Ltd., the leading Canadian skylight manufacturer, has produced products of the highest quality, designed to meet the challenging demands of our climate. Our product line is innovative, and utilizes industry leading materials. Our gold standard warranty supports our product line, and it has withstood the test of time. Columbia has been building skylights that you can count on, for over 65 years. Curb Mount skylights are the preferred skylight choice in Canada for any type of roof; primarily for use on tile, shingle or wood shake roofs. Recommended by roofing professionals as the optimum choice for long lasting, trouble free installation. Other skylight types include built in wood curbs for double the cost.LoE3 clear glass is the industry standard and features a dual pane filled with argon gas, providing superior condensation resistance and blocks 95% of UV rays. MINIMUM 2:12 ROOF PITCH IS REQUIRED for all glass VCM/OVCM skylights.