A skylight is basically a window in a roof. Its frame is designed to withstand the rigors of weather, and its flashing works with the roofing material to seal out rain and snow. A roof window, which pivots at the center, is designed for use in an attic room.

Some older skylights leak because of poorly sealed flashings. Others drip because of unchecked condensation that collects when warm room air comes in contact with a skylight's cold inner surface. Leaks can usually be fixed by resealing the flashings. Condensation is tougher to correct; it calls for improving a house's ventilation.

Newer skylights are virtually leak-free, thanks to rugged construction and easy-to-install, integral flashings. They're also equipped with channels that carry away condensation. Although some frames are solid wood or aluminum, most new skylights are made of a combination of metal, vinyl, and wood. The exterior frames tend to be aluminum cladding with a durable finish; the part visible from inside is often made of solid wood, plywood, or white vinyl.

Some skylights are glazed with acrylic or polycarbonate, others with glass. Plastic versions are lightweight and economical and are often used where a glass skylight could be easily broken. Because they're molded, they come only in standard sizes and shapes: flat rectangles, bubbles and domes, pyramids, and dormer models, for example. Some skylights open a few inches to allow air circulation. They're usually operated with a pole, but motorized versions are also available.

Repairs: Dealing with a pesky leak or a loose latch on a skylight can be a tricky task, because of the angle of working above your head, and if you're outside, working on a steep pitch. The repair might be best left to a Service Professional with the proper equipment and necessary experience.

-- Tips courtesy of HomeAdvisor.com