Skylight / July 8, 2018 / Baptiste Allain
The acrylic dome is typically mounted in an aluminum frame which is in turn mounted on a box called a "curb." Once the hole is cut in the roof to the manufacturers specifications the curb is typically constructed on-site to raise the skylight above the level of the roof sheathing. Site-built or factory-supplied flashings are used to seal the roofing around the curb. Domed skylights are available in clear smoked bronze or other tints. Some domed plastic skylights are flush mounted which means that the lens piece and flashing piece are both made of plastic and then placed on the roof without a curb. The problem with this type is that they are loud and very susceptible to leakage.
After the hole is cut the skylight frame is simply attached to the roof sheathing with L-brackets and then the installation is completed using the factory-supplied flashing kit. Ease of installation superior insulating qualities less tendency to scratch and a cleaner finished appearance all add to the popularity and somewhat higher cost of glass skylights. Glass skylights also have a greater number of optional accessories. These include tempered laminated or wire glass; shades and blinds for light control; glass tints for heat retention or to block sunlight; and the ability to open fully or partially for ventilation. Domed acrylic skylights are less expensive than glass.
However these surfaces scratch easily and can become brittle and discolored. Glass glazing - This is found in the more expensive skylights. It is more durable than plastic and does not discolor. All glass used for skylights must be made of "safety glazing" a generic term for both tempered and laminated glass. Tempered glass is the most impact resistant. Laminated glass is fabricated with a thin layer of plastic embedded near the center of the glass. Both types keep the glass from breaking into large sharp pieces. Skylights are often made with a tempered glass on the exterior side and a laminated pane on the interior side. This arrangement gives maximum impact resistance while protecting occupants from falling shards of glass.