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Terminology
Curb - the frame the
skylight is mounted on, which can be either integral to the
unit as in a self-flashed skylight, or a separate piece as
in a curb-mounted unit. Curbs are usually made of either 2
x 4’s or 2 x 6’s, though unusual applications
may call for a larger curb. A curb should always be insulated,
preferably with underlayment and flashing.
Outside curb dimension
- the dimension most commonly quoted when ordering or quoting
skylights. The OCD is usually ½’’ shorter
per dimension that the “make size” or the measurement
from vertical flange to vertical flange. For example, a 25
½’’ x 49 ½’’ outside
curb dimension will yield a 26’’ x 50’’
make size skylight.
Energy Star - A rating
program sponsored by the EPA and Department of Energy which
provides energy saving standards met by several of our product
lines.
Flashing - the weatherproofing
system that is either integral in your unit as in a self-flashed
skylight, or separate as in a curb-mount. Flashing can be
made to match any roofing material, and can be interwoven
as in the case of step flashing to shingle roofs to seal the
skylight without sealants that can break down over time.
Glazing - a term descriptive
of the light part of the skylight, in other words, the part
you see through. Skylights will always be double-glazed, or
will have two layers, otherwise you are looking for a “hatch
cover”.
Tempered glass - a standard safety function that allows glass
to shatter into small pieces rather than large dangerous shards
Laminated Glass -
the lower layer of glazing is made of two panes of heat strengthened
glass bonded together around a vinyl layer that holds the
glass together if it is broken. Laminate is an additional
safety feature made for areas more prone to extreme weather
or that sit directly under or in close proximity to trees.
Low E - is a microscopically
thin film on a glazing surface that suppresses radiative heat
flow through the skylight. Also known as a spectrally selective
coating.
Argon - is an inert
gas that provides added insulation windows and skylights
Acrylic - used most
often on flat roofs due to it’s natural dome shaped
once formed, acrylic is an inexpensive alternative to glass
that is lighter and can be used in a wider array of applications
Polycarbonate - also
lightweight and particularly impact resistant, most skylights
made with polycarbonate use a flat sheet design which has
the benefit of being more durable than acrylic or glass, but
is often not completely translucent and can’t be used
in as many applications
Cladding - part of
the exterior aluminum framing of the skylight
R and U values - U
value is the measure of heat flow through the glazing surface
of the skylight expressed in units of Btu/hr-ft2 -deg.F The
higher a skylights U-value, the lower its insulating value.
An R value is the inverse of the U-value, expressed in units
of hr-ft2 -Btu. The higher the R value is the greater resistance
to heat flow, and accordingly the greater insulating factor.
Underlayment - another
level of protection from the elements that most contractors
use to “wrap” the curb of a skylight and we always
recommend using where possible.
Pitch - the angle
of your roof or the ratio of rise to span that will often
determine what kind of skylight you can use. For example,
a 15 degree (or 3/12) pitch is often the lowest a flat glass
unit can be applied to without custom building a pitched curb
and/or voiding the warranty. This is an often over-looked
aspect of buying a skylight.
Sash -the part of
a venting unit that opens out, or the frame in which the glass
panes are set
Glazing Options
Clear glass or acrylic will always
afford you the most light entering your house, however if
you are concerned about the room’s exposure to UV radiation
[finish this text]
- Glass Options
- Tempered over tempered glass
- Tempered over tempered with Low-E
(Low-Emissivity, an invisible film stretched between the
layers)
- Gas filled
- Tempered over Laminated (the laminate
is a safety option)
- Tempered over Laminated with Low-E
- Tinted glass - gray and bronze are
standard colors, almost any other color is possible, though
considered custom
- Tinted acrylic - bronze, white and
gray are considered standard and will add very little to
your price; most other colors are custom
Frame Color
The frame color will change depending
on material; unfinished aluminum will be a different color
than copper, but almost any color can be applied (usually
using baked enamel on top of a anodized frame). Bronze (a
dark almost black) is used most often as it matches standard
shingles perfectly.
Applications
Flashing Kits - Flashing,
usually L-shaped aluminum or copper bent to the specifications
of your skylight that is necessary to make your unit weather
tight, can often be purchased as a kit made specifically for
your unit. If one is not available from the manufacturer which
is often the case for a custom size, your contractor should
be able to construct his own rather easily.
Self Flashed - A self-flashed
skylight incorporates all three pieces: the skylight, curb,
and flashing into one, easy to install unit. Self flashing
is an option that can be adapted to almost all skylight models.
Curb Mounted - a term
describing a skylight without an integral curb (the frame,
usually wooden, that is between the skylight and the roof).
Curb mounts are often desireable for more extreme roof pitches,
though often the choice between self-flashed or curb-mounted
is made according to what the contractor has more comfort
installing.
Flat Roof Curbing Systems
- Very simply, flat roof curbs add pitch to glass skylights
and are tremendously convenient (and necessary) when adapting
a flat glass unit to a flat or low pitch (below 3/12 or 15
degree). Your contractor can sometimes fashion his own curb
to allow for pitch, but this can get complicated and will
often void the warranty of your unit.
Tandem Systems - Tandem
or grid systems are an easy way to adapt multiple skylights
to one roof and are often inexpensive as they usually incorporate
standard sizes into aluminum extrusions (frames).
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