Don Vandervort, Head Homeboy, has written more than 30 DIY home improvement books, been a segment host on HGTV, served as MSN.com's home improvement expert and written countless magazine articles.
Skylights come in many standard sizes that run from about 14 inches square to about 4 feet square, though you can buy larger sizes. Of course, not all skylights are square—rectangular skylights, often preferred for sloped roofs, are manufactured in sizes up to about 8 feet long.
Where a larger-than-standard skylight is wanted, designers usually group a series of smaller units together or specify larger custom sizes.
Several companies make special flashings designed for grouping their skylights together. Larger custom sizes, which are extremely heavy, almost always require glazing at the site.
How big should a skylight be? There are no hard and fast rules. Some companies recommend sizing a skylight to be 5 percent of the room’s floor space for ordinary activities, 10 percent for frequently used work areas and 15 percent for kitchens, family rooms, home offices, and other heavy-duty work areas.
