Skylight / July 11, 2018 / Nicolas Charlebois
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.
Glass and acrylic or plastic skylights are available. Tubular skylights are relatively new on the scene. The small size allows them it to be used in spaces where full-sized skylights cannot. Hallways bathrooms even closets can accommodate a tubular skylight. They provide a lot of light in spite of their small size. The concept and installation process are basically the same as for a regular skylight except they have an enclosed tunnel of reflective material to reflect the light. They are available in many sizes. The small ones are 10 to 12 inch diameter and the large ones are 24 inches. Flat glass skylights come mounted in a wood or integrated rubber and metal framework and require no additional curb construction.
For example the optimum slope for a south-facing skylight in Columbus Ohio at 40º North latitude is 45º to 55º. Every skylight has a "shaft" which governs how much light is admitted into the room below. If all four sides are flared then the light is spread over a wide area. If your skylight has a shaft with perpendicular sides the light is focused straight below. If your skylights shaft is flared on only one or two sides then the light is sprayed in the flared direction. Ventilation If you wish you can have a skylight which also provides ventilation as well as light to your room. This allows you to release the hot air which collects at your ceiling.