What is the difference between skylights that are “deck-mounted” and those that are “curb-mounted”? Curb-mounted skylights sit on top of a framed opening in the roof. Deck-mounted skylights fasten directly to the roof sheathing, negating the necessity for a framed curb.Click to see full answer. Keeping this in view, what does deck mounted skylight mean? Deck-mounted skylights A deck-mounted skylight is directly attached to the roof deck. It comes with a built-in frame/curb, and you need to seal i, using waterproof materials (underlayments). A flashing kit is also used to cover the seam and the underlayment, to make the installation water-tight.Beside above, how often do skylights need to be replaced? 1) Roofing material usually has a life expectancy of 20 to 40 years. Not replacing the existing skylight at the same time as you replace your roof would be to expect your skylight to last another 20 to 40 years! 2) Replacing an existing skylight is much harder and more costly after the roof is installed. Accordingly, what is a fixed curb mounted skylight? Curb mounted skylights are the most common skylight type. This design requires a box structure for the unit to sit on. Generally this box is comprised of 2×6, or larger, construction lumber set on edge and attached to the roof deck. The skylight is designed to sit over the curb like a lid on a shoe box.What are the different types of skylights?There are three main types of skylights, ventilating (sometimes called “roof windows”), fixed, and tubular. They come in a range of different shapes, including flat, arched, domed, and pyramid.