Curb-mounted skylights sit on top of a framed opening in the roof. Framing materials are fastened directly to the roof sheathing, then flashed (thin pieces of impervious material installed to prevent water entry around openings), before a curb-mounted skylight is fastened to the top of the curb. Deck-mounted skylights fasten directly to the roof sheathing, negating the necessity for a framed curb.
Curb-mounted skylights are typically a more economic option for a new house, while deck-mounted skylights save money on existing houses by reducing installation labor. Additionally, deck-mounted skylights have a lower profile and may be more aesthetically appealing. Both curb-mounted and deck-mounted skylights are available in a variety of glazings and claddings (claddings hold the skylight lense to its frame) and can be fixed, manually venting, or electrically venting models.