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.
For one thing skylights are positioned in such a way that they are inaccessible unless they are operated by remote. Even in cases of motorized skylights which are easily manipulated there are still some disadvantages that are inherent to skylights that are not present or minimized in windows. Vertical windows lose less heat by convection when compared to skylights. Also since windows are generally protected by overhangs or shrubs they lose less heat by radiation. On the other hand skylights are directly exposed to the sky. Thus they lose more heat by radiation. Proper insulation can reduce this heat loss to a large extent. In the summer season skylights are more exposed to the direct heat of the sun than windows.
For instance flat roofs are more susceptible to drainage problems. Flat skylights on flat roofs may lead to water pooling. That is why experts recommend the use of domed skylights on flat roofs. This promotes drainage. Skylights for low pitch installation generally have significant slope built into the design. Attention must be paid to such things before installing skylights. Skylights are introduced into the design and architecture of the home to bring in lots of light heat and warmth. But what happens if there is a tall tree towering over the skylight on the roof? The very purpose of the skylight is defeated. The position of the skylight on the roof plays a vital role in determining its usefulness and effectiveness.