Planning a Skylight
Keep in mind one important fact:
A skylight will only work in a room that is either directly below the roof or
is below an unfinished attic space.
If you want to install a skylight in a room that has an attic above, you’ll
need to build a light shaft through the attic.
The shape of a light shaft controls the spread of the natural light beam.
A shaft that’s flared on all four sides spreads light over the widest area.
A perpendicular shaft with vertical sides focuses the light straight below.
A shaft flared on only one or two sides sends more light in the direction of
the flared sides.
When planning a skylight installation, be sure to take into consideration
the sun’s path. Skylights on the south- or west-facing portion of the roof
will collect direct sun - skylights facing north or east may not get any
direct sunlight. A skylight that receives direct sun can become an intense
heat trap in the summer unless it includes shades, blinds, or some form of
controlling sunlight.
Similarly, a skylight placed in a bedroom can offer a nighttime view of the
stars but, if it doesn’t have some form of daylight blocking shade, it can
also offer a rude awakening at daybreak. Of course, any skylight that is
intended to provide a view must be kept clean, so ease of maintenance
becomes a factor in choice of location and the type of skylight.
Sizing and placing a roof window in an attic room so that it captures a
view calls for careful planning. The roof’s slope will affect proper
placement. A low-sloping roof will require a taller window than a steeper
roof for the same amount of view. Manufacturers of roof windows have
charts that list recommendations based on the slope of the roof.