VELUX skylights are built at our manufacturing sites where we run extended internal audits to monitor compliance with all critical safety standards. They are then packaged with everything a roofer, builder, or general contractor needs to install the skylights and flashing kits. And when it comes to installation, VELUX has made it as simple as possible to do by eliminating mistakes that can lead to leakBoth VELUX deck-mounted and curb-mounted skylights include three layers of protection from water leaks. Each type of skylight has a unique first layer to protect against leaks: the deck-mounted skylights have a deck seal while curb-mounted models have a pre-attached skylight gasket.