Today's sunrooms aren't what they were just a few years ago —
there are many more options. You can now get a prefabricated
sunroom that will satisfy nearly every design and budget. Even in
expensive homes, where several years ago you would have had no
choice but to custom-build a structure, chances are good that you
can now find a prefabricated structure to fit the bill. But you
have to work with the manufacturer to make sure you get what you
and your customers want and that the structure performs to
everyone's satisfaction for the long run.
The results of such persistent research pay off. At least that's
what West Palm Beach, Fla., architect Sam Rosenberg found when he
took on the renovation of a 10,000-square-foot home in Manhasset,
N.Y. A former seaplane hangar, the home is perched on the edge of a
granite seawall, with a tall A-frame roof that faces the ocean and
encloses a multi-use great room with a fitness area and swimming
Rosenberg says that his first design called for enclosing the
50-foot-wide by 10-foot-tall opening beneath the A-frame with a
custom-built glass and wood-framed wall. But the cost was too high
even for this home's wealthy owners. Instead, he found a movable
sunroom made by Roll-A-Cover International in Bethany, Conn., that
had been on the market for three years. This product has
6-foot-wide sections that slide open from the center and stack on
top of one another at either end of the opening. Not only did
Rosenberg save a lot of money, but he believes the quality of the
end product is better than what he could have had built on site.
"Because the frame is made from aluminum, it has very little bulk
to block the view. You can look out from the fitness room, across
the pool, to the ocean view in winter." And in summer, the
homeowners can turn the space into an outdoor room. When severe
storms blow in from the Atlantic, the stacked sections can be
strapped together and the sill bolted down with pegs that fit into
sleeves embedded in the concrete deck.
Even on a high-end project, budget is a deciding factor. The
architect saved a lot of money on this Long Island house by using
the Roll-A-Cover product on the end of the house facing the ocean
rather than custom-building a sunroom. According to the
manufacturer, a system like this will cost $90 to $100 per square
foot of floor area beneath the horizontal glazing.
CHOOSING A SYSTEM
New product choices may help explain why sunroom sales have grown
so much in recent years. A 2003 Wall Street Journal article
reported 40% growth in the three prior years. Costs can range from
$10,000 for a basic enclosure system upward to $50,000 and above
for an elaborate conservatory.
Those numbers don't include glassed-in room additions that are
thermally connected to the rest of the house. Such rooms tend to be
stick framed and have to meet the same code requirements for
structural strength and thermal perfor-mance as any other room.
Instead, most of the sunrooms counted in the above stats fall under
International Residential Code's definition of Patio Covers,
defined in Appendix H as rooms "used only for recreational, outdoor
living purposes, and not as carports, garages, or habitable rooms."
These consist of prefabricated units with aluminum or vinyl frames
and insulated glass and foam infill panels.
Sunroom manufacturers compete on design and construction. The
biggest design distinction exists between sunrooms and solariums. A
sunroom has glass walls but an opaque roof, perhaps with skylights.
A solarium has glass walls and a sloped glass roof. (A third
category, the conservatory, is a more geometrically complex
English-style solarium.) The companies mentioned here will all
custom-design and engineer a sunroom for your project, but it's a
good idea to ask a lot of questions about each product's
limitations. For instance, one manufacturer might use stock-size
windows and fill in odd spaces with foam panels, while another
might custom-fit sheets of glass and cut them to size.
Vinyl vs. aluminum. Frames may be made
from extruded vinyl or aluminum, and this is where making
comparisons may require some due diligence. Impartial information
can be very hard to find, and because the sunroom business is
extremely competitive, manufacturers routinely savage one another's
product. One maker of aluminum sunrooms advises that vinyl won't
stand up to high winds, even if reinforced with metal. The people
who sell only vinyl systems deny that charge and counter that
aluminum is overpriced, will pit and discolor in the salt air, and
will conduct enough heat to and from the outside to make the room
Joyce Manufacturing's Leisure Room 3000 is its top-of-the-line
vinyl product, an "all-season" with sliding windows that tilt in
for cleaning. The windows use tempered insulated glass with a low-E
coating. Approximate cost for the 18-foot by 12-foot room is
Should you worry about the strength of a vinyl sunroom? It depends
on whom you ask. "Although our solariums are aluminum, it's not a
structural issue, since vinyl has to meet the same code and wind
requirements," says Tony Bouquot, director of engineering with
Patio Enclosures, Inc. in Macedonia, Ohio. But others say that
there's a point at which vinyl becomes impractical. "It depends on
the size of structure. Aluminum can be engineered for larger
spans," says Ken Sekley, Patio Enclosures' COO. "It gets to a point
where loading up a vinyl structure with steel drives up the cost
too much. That makes aluminum more economical for a larger-sized
As for aluminum's energy performance, if the room will be heated or
cooled, look for a product with thermally broken frames that reduce
the heat transfer between the interior and exterior. For instance,
the SF-70 model (designed to meet hurricane codes), distributed by
Phoenix, Ariz.-based Sunflex USA, uses aluminum extrusions whose
inner and outer faces are joined with polyamide, a high-tensile,
fiberglass-reinforced plastic that limits the conduction of
Aluminum frames are generally protected with a surface coating,
often a baked-on enamel. Some manufacturers, such as Sunflex and
Roll-A-Cover, use a powder coating on their products. Roll-A-Cover
offers a 10-year warranty on its powder-coated finish.
Each manufacturer also has its own menu of options and
enhancements. If you want an overhead light, for instance, some
frames have built-in raceways for electrical wiring, while others
require you to surface-mount conduit. Some companies offer internal
roller shades — either motorized or hand operated —
that cover the roof and walls of their solarium products, while
others put mini-blinds between the panes of glass. Some offer
self-cleaning glass (a coating on the glass uses the sun's energy
to break down dirt, which then washes off when it rains). Patio
Enclosures offers glass with built-in, low-profile safety rails for
balcony projects. Berea, Ohio-based Joyce Manufacturing treats the
foam insulation in its sunroom wall and roof panels with TCA guard,
a mineral designed to repel termites and other wood-boring
The glass panels used in a sunroom can range from 5/8-inch single
pane to 1-inch-thick insulated glass to laminated glass. There are
two issues when it comes to windows: energy performance and impact
Energy performance. According to Bouquot,
the energy requirements for sunrooms are "specific and
prescriptive." For instance, the glass used in a sunroom that's
thermally isolated from the rest of the house has to have a maximum
U-value of 0.5. To meet the energy requirements, manufacturers
offer a variety of low-E coatings, which limit radiant heat
exchange between panes by reflecting heat back into the home during
cold weather and back to the outdoors during warm weather. The type
of coating can vary depending on where the window is installed. "We
use a stronger low-E coating on the roof glass than on the walls,"
explains James Ruppel of Four Seasons Sunrooms in Holbrook, N.Y.,
"because in winter when the sun is lower you want to allow heat
gain in." A variety of tints are also used to reduce heat gain as
well as ultraviolet rays.
Structural performance. Building codes
require that safety glass be used for all horizontal glass (glass
facing or angled to the sky and the floor) and for windows that are
lower than 18 inches from the floor.
This aluminum-framed, curved-eaves solarium from Patio
Enclosures, Inc. was built on an existing roof of a Maryland home
for approximately $44,000. This sunroom features insulated Azurlite
glass with a slight blue tint that reduces solar heat gain and UV
exposure and cuts down the glare for an enhanced view. Roller
shades offer privacy and added sun protection.
Safety glass can be tempered or laminated. Tempered glass is
heat-treated to be ten times stronger than untempered glass, and
when it does break, it breaks into small pieces without sharp
edges. Laminated glass comes with a plastic interlayer. It's the
same glass that's used on hurricane-rated windows. Because of its
high cost, manufacturers specify laminated only where it's required
by code, so if you want to use it elsewhere, you'll have to ask.
Roll-A-Cover CEO Michael P. Morris says that his company uses
1/4-inch-thick tempered glass on all vertical walls and a 1/4-inch
non-acrylic polycarbonite material on the horizontal portion. (The
company guarantees the poly against cracking for 10 years.)
Better manufacturers have engineering departments that design the
room to fit the house and to conform to local codes. As part of
this service, they should provide engineering drawings for
submission to the authorities.
Some companies offer high-wind products with laminated glass and a
glazing system that meets the code-mandated impact and design
pressure requirements for hurricane zones. "Look for a manufacturer
that has documented engineering for its product," advises Ruppel.
"That should include testing for cyclic loads and impact
The engineering should specify how much weather the sunroom can
withstand. For instance, Joyce Manufacturing executive vice
president Gary Winkler says his company will build sunrooms with
wind ratings of up to 140 mph. John Hickey, with Southern Exposure
Sunrooms in Wilmington, N.C., installs the Sunflex product, but
will also custom-build sunrooms using component parts from various
manufacturers. He says he can offer a custom product with laminated
glass and an interlocking aluminum frame that stands up to winds in
excess of 146 mph and can withstand impacts from a Category 4
Some products have special requirements for storm resistance.
Morris says that Roll-A-Cover is manufacturing a 46-foot-deep by
100-foot-long pool enclosure for an 18-story condo project on the
ocean in Alabama. He says the room will meet the requirements for a
140-mph wind load. In order to do so, however, the sections have to
be opened and strapped down before a storm comes ashore.
Some manufacturers run their businesses like a standard
subcontractor by selling only installed systems, and installation
is often done only by franchised companies. Others will let the
builder's crew do the installation. If you decide to go this route,
ask a lot of questions about the company's training and technical
support. For instance, Sekley says that Patio Enclosures will
provide the builder with shop drawings, an installation manual and
video, and can even send a project manager to supervise the
Regardless of who installs the sunroom, the builder is responsible
for site prep. Getting this right can make or break the project. As
is true for any panelized structure, the foundation for a sunroom
has to be close to perfect. "If the area to be enclosed is
mismeasured, there's not a lot of flexibility with glass on site,"
notes Sekley. That's why it's best to order the sunroom after the
deck or slab is in place. "The builder has to complete the deck or
patio, then take field measurements for each unit before we begin
making the order."
Sunflex installed this folding wall system on a private
residence in Connecticut. Cost is about $2,000 for a 3- to
4-foot-wide panel. The system can be custom-manufactured to fit any
Getting things right in the field is even more critical for moving
systems. "We ask a lot of questions about site conditions," says
Morris. The site needs to be level, plumb, square, and
perpendicular to the house. "The measurements have to be almost
bone up for the enclosure to work properly, because we can't adjust
the wheels." The strip beneath the wheels has to be dead flat.
"We've had a few customers who, even after we tell them that we
need a flat surface, will install stamped concrete, so there are a
lot of caps and grooves." All that's needed, says Morris, is a
narrow strip beneath the wheels. Properly installing this strip
means that the builder has to heed the manufacturer's specs.
This straight-eaves sunroom from Four Seasons uses northern
white pine glulams as a framework for insulated glass panels. The
company uses two different glass formulations: The roof glass,
which is designed to control heat gains during the summer, has a
solar heat gain coefficient (SHGC) of .15 and a U-value of .25. The
vertical glass, which allows the warmth of the low winter sun to
warm the interior, has an SHGC of .33 and a U-value of .25.
Material costs for this model are $18,000 to $20,000. Labor costs
vary by region, but run about 40% of total job cost to over 50% in
areas with lower labor costs.
Of course, getting any part of the installation right means that
the builder should also be willing to ask any of his own questions.
But a builder who has done the research to choose the right system
for his project will already understand the importance of leaving
nothing to chance. ~
Charles Wardellwrites about building science
and technology from Vineyard Haven, Mass.