12061 Jefferson Blvd., Culver City, CA 90230-6219
Within the past year, there has been a surge of interest in prefabricated steel stud panels with ceramic tile exterior surfaces. The Ceramic Tile Institute believes this subject to be significant to,CTI members and.have obtained permission from TILE & DECORATIVE SURFACES MAGAZINE to pre-print a feature story on this topic which appears below:
There are very positive signs
other elements were then custom-
hand-setting of tiles may be advan- around today that the ceramic
tile
formed which priced the system out
tageous.
industry is moving into such an op-
of the market for that time. Today,
From initial design stages through portunity. It has been gradually
the situation is reversed. Prefab
final installation, technical services building up for several years
and
panels are now more competitive
are available without obligation to ready to become a reality ... an
ex-
(often by a big margin) than glass or
architects and contractors for can- plosive opportunity for growth
to
aluminum curtain wall, precast con-
sultati6n, drawings and specifica- those who are prepared and
aggres-
crete, masonry, etc.
tions.
sive.
ADVANTAGES OF PREFAB In
brief, prefabricated ceramic Tile contractors, distributors and
Prefabricated panels installed
tile panels on steel stud framing of-
manufacturers of tile and related
over gypsum sheathing, framed
fer the following advantages: products should commence re-
with lightweight steel studs, com-
Eliminates tons of costly deadload search, training and marketing
prise a new system for high-rise in
design and requires less struc- plans if they plan to profit from this exterior walls
where permanent ar-
tural mass since panels weigh ap- new frontier.
chitectural beauty, surprising econ-
proximately 80%
less than brick
The new market is in: prefabri-
omy and most efficient scheduling
or pre-cast concrete; cated, exterior tile panels framed
are desirable or necessary.
Significantly less expensive than with lightweight steel
studs.
Although steel stud prefabricated
glass or aluminum curtain walls
Although the basic concept is not
buildings have a long and success-
... superior insulation capability, truly new, this system has now
be-
ful history, this marks the first time
more energy efficient;
come economically feasible due to
that a system has been available na-
Eliminates costly scaffolding ... recent, cost-reducing production
tionally using exterior facing of the
panels arehoisted by lightweight line methods of making lightweight
most prestigious and permanent
lifting gear such as rooftop rigging steel studs and other elements in
the
material ... ceramic tile. The light-
and welded into position from the system. Thirty years ago, the can-
weight,panels are assembled and
inside of
the structure;
I
* Panel cavities provide a chase for 1979 year for the United
States.
treated paper back. These are pipes and wiring along exterior
Obviously, prefab tile exteriors screwed to the studs
with self-tap- : walls, for faster, easier and more are not for every office
building, ping
screws over washers. This is economical installation;
hospital, school or other building. followed by two 3/8"
coats of port- - Exterior ceramic surface is vir- However, many,
many contracts
land cement plaster, latex modified tually maintenance-free;
requires now
going to curtainwall, concrete portland cement bond
coat and then
system is the method of affixing the
panels to the structure of the build- I . @ I
-
Factory supervision and quality for economy reasons alone. Block system is the
method of affixing the control assures utmost accuracy, and brick, for example,
do about 10 panels to the structure of the build- closer tolerances and more
consis- times the sales of tile
according to ing, which has a steel frarne and tent results;
the U. S. Department of Commerce. Doured-in-niari- ronrr,-.t,- flnnrq
CTI 80-12-10 (P,-AS)
no painting, acid-cleaning, or ren- ovation;
tent results; •Rain, snow and freezing tempera- tures do not delay completion schedules since panels are con- structed in enclosed building;
•Superior resistance to wet weather compared to other pre- fabricated panels;
•Tile exteriors are permanent and non-fading and frostproof ... aes- thetic additions to any community, forever;
•Exclusive keyback ridges on some ceramic tiles permanently lock tiles into portland cement mortar in panels for superior margin of safety.
THE
MARKET POTENTIAL According to some respected con- struction industry executives,
pre- fab tile panels represent one of the most exciting and explosive growth
potentials for ceramic tile in the next decade. It's a concept, they be- lieve,
whose time has come. Ac- cording to latest F. W. Dodge Statis- tics,
non-residential construction (office buildings, commercial stores, schools,
hospitals and manufactur- ing) construction in 1979 was almost $50 billion
dollars. Exterior walls for these buildings consume 3-11% of the total
construction costs (for brick, block, stucco, curtain wall glass or aluminum,
etc.) which boils down to a conservative $2.5 billion dollar market each year.
Up to now, ceramic tile has captured an insig- nificant share of this potential
due to various reasons (scaffolding costs, weather limitations, etc.) but now
the situation has changed 180 de- grees.
If tile can capture 5% of this exte- rior market, the potential is $250 million per year. Even at a conser- vative 2%, the volume will be $100 million per year which is more than 10% of the total tile market in the
or masonry would be excellent the tile.
prospects for the prefab tile system Crucial to the success of this new
the U. S. Department of Commerce. Class and aluminum curtainwall (now on a downhill trend due to poor insulation qualities) cost at least 307o more than installed pre- fab tile panels.
PIONEER
PROJECII DENVER, COLORADO
In September, 1980, the first mod- ern-day high-rise with prefabri- cated ceramic tile panels was com- pleted in Denver, Colorado ... the stunning 12-story Lincoln Court Building. The Lincoln Court office building was designed by McMor- ran Obermeier Goss Bershof Archi- tects (better known as "McOG") and erected by'lbmer Construction Co., general contractor. Tile was laid by Ace Tile & Terrazzo Company in lightweight steel stud panels made by John Burke, Inc. The tile is Gail Unglazed Red Range Brickplate with brown and black flashing to provide iridescent blending of col- ors within each panel. The keyback ridge design in Gail Brickplate locks the tile permanently into the mortar bed for an extra margin of safety.
FABRICATION
AND ATTACHMENT OF PANELS
All panels were assembled and finished indoors, a great conve- nience in Denver's winter weather, then transport ed to the job site. While other projects may require different arrangements of steel, backing and attachments, the Den- ver panels demonstrate the basic idea.
They were framed by 16-gauge punched steel Cee studs 6" wide, on 24" centers, and rest on tracks of un- punched 18-gauge steel. Each roughly-two-inch-thick panel is backed by 1/2" asphalt impregnated gypsum sheathing (core treated) on which is placed self-furring ex- panded metal lath with asphalt
.@
back.
poured-in-place concrete floors. Three-foot-long 2" x 2"
x 3/is" clip angles were welded vertically to the spandrel beams all the
way around the building, including comers. The steel studs of the tile panels
are welded to these angles, making a sturdy and permanent installation. Class
fiber insulating batts, 6" thick, are placed between the studs.
READILY AVAILABLE MATERIALS
The basic elements of the new- style walls are light
gauge steel stud- ding, and joists. These are prac- tically off-the-shelf items
available throughout the country from many manufacturers-su'ch as Bostwick,
Inryco/Milcor, U. S. Gypsum, U. S. Steel and others. Assembling and erecting of
the steel framing can best be done by journeymen lathers rather than
iron-workers or carpen- ters. The remaining materials: asphalt impregnated
gypsum sheathing, self-furring lath, cement, gypsum wallboard and- tile
are also available everywhere.
Different methods of anchoring the panels to the
building may be devised according to need, as long as the whole affair conforms
to local building codes. In addition to code requirements, it is advisable to
as- certain allowable,spans from the supplier of the steel framing as pro-
tection against wind and seismic overloading.
It cannot be emphasized too strongly that fabrication
and fasten- ings must be of top quality for per- manent reliability. Also, the
tile selected must be of a frostproof type that resists local weather
conditions.
The very nature of tile panel con- struction helps
induce the highest standards of quality control. Since panels are made under
shelter, they can be fabricated with extreme ac-
CTT AO-12-10 (A-9s)
curacy, closer tolerances and more consistent results.
For the same rea- son, completion schedules are not delayed by rain, snow and
freezing.
At the construction site, this type of framing
facilitates rapid forma- tion of window and door headers. it also tends to
distribute and dissipate strains throughout the entire struc- ture. It is,
however, recommended that the architect and design en- gineer consult with the
panel pre- fabricator right from the start.
FIRE RESISTANCE The various components of pre-
fabricated exterior tile panels are made of non-combustible materials and
generally carry a flame spread and smoke density rating of zero. After fire
rated gypsum wallboard is attached to the interior flange of the steel stud
framing, most building codes qualify the wall as a one-hour fire-rated system.
TEMPERATURE CYCLING TESTS
'lb prove that the Gail Brickplate panels used on the
Lincoln Court Building were durable under ad- verse conditions, tests were con-.
ducted by an independent testing construction research
laboratory in 1980, which subjected a panel to se- vere temperature changes and
freeze-thaw conditions to simulate extreme weather conditions.
The test panel was constructed identically to the
prefabricated wall panels used on the Lincoln Court Building in Denver,
Colorado. The
exterior surface of the panel was subjected to 150
heating and cooling cycles alternating from 25 degrees F to 145 degrees F with
each tempera- ture extreme held for 15 minutes.
The panel was also subjected to twelve freeze-thaw
cycles in which the panel was covered with 1/4 inch of water
and frozen to -20 degrees F. The average cycle time was four hours with complete
thawing after each freezing phase.
The laboratory reported that there was no evidence of
any, damage or cracking resulting from these tests.
A final word: All reasonable clearance between panels
and structural members for adjustments in vertical, horizontal and rotational
positioning. The use of metal shims or other adjusting devices to align panels
is recommended,
While details may differ from one locality to another,
these easy-to- erect prefabricated tile panel walls offer the multiple
advantages of lightweight, economy and mainte- nance-free permanent beauty.
SOURCES OF INFORMATION Already some of the more aggres-
sive major companies have been planning and preparing for the fu- ture growth of
prefab tile panels.
Probably the most experienced is Gail Ceramics, Orange,
California, which supplied the tile for the Lin- coln Court Building in Denver
and worked closely with the architects. Gail has prepared excellent techni-
cal information, brochures and slide presentations on the system and also has an architectural consultant on staff to answer questions and as- sist in problem solving, estimating and detailing. Since Gail was the first to be involved in a major prefab job, their experience is also advan- tageous to a firm anxious to learn and expand. Moreover, Gail has a special "keyback ridge" on the backside of their tile which serves as a sales lock-in advantage when an architect or engineer is worried about the tiles failing five floors from the surface of the structure.
Huntington-Pacific has also been active in this market and has pro- duced a slide presentation on the system which has been shown at in- dustry meetings in recent months.
For counsel on the installation of tile over the sheathing, the Lathing Bureau has information available.
In one year, dozens of companies will be jumping on the bandwagon but only a few of the better financed firms are prepared right now to help without obligation.
SUNLNIARY
The tile industry is on the thresh- old of a major breakthrough for growth. Not
every contractor is geared for this work: it is for the me- dium and big
operations. But, the potential looks very bright. Ag- gressiveness in learning
sales, train- ing and risk-taking can pay big divi- dends for these firms.
INTRODUCTION
Architects and builders, wanting to reduce dead load,
construction time and costs, are more frequently utilizing light gauge steel
stud framed panels with any of several different finish Tnaterials to construct
exterior walls on their building. Tile and masonry veneer are two of the-most
desirable finish materials designers would like to use on their buildings;
however, they are concerned with the cost.
Remarkable cost savings are possible when the steel stud
panels with a tile finish are fabricated-off the iob site, then shipped
to the job and hoisted
in place. The panels are simply but securely welded to
the structural frame of the building.
Steel studs and tracks are roll formed sections usually
fabricated from metal in thicknesses of 16, 18, 20 or 25 gauge. They may be
fabricated from galvanized steel or are available painted with rust inhibitive
paint. Steel studs and tracks are available in widths
of 2-1/2", 3-1/4", 3-1/2", 3-5/8", 4" and 6" and in
lengths cut to order, up to 20' - 30'.
TERMINOLOGY
There are a few terms and definitions which should be
understood to be familiar with Prefabricated tile panel construction,
1. STEEL STUDS AND TRACKS
PANELIZING EXTERIOR WALLS WITH STEEL STUDS, LATH;
PORTLAND CEMENT PLASTER AND CERAMIC TILE
Panelizing Exterior Walls with Steel Studs, Lath,
Portland Cement Plaster and Ceramic Tile
FM
STUDS
There are over a half a hundred different types, sizes
and gauges of steel studs, so care should be taken to select the most
appropriate one for any particular application.
The webs of steel studs typically contain punchouts
through which electrical and mechanical lines can be run. The punch- outs also
serve to reduce the weight of the sections.
RUNNER TRACKS
Runner tracks, which secure the studs at the top and
bottoms of panels, do not have punched webs. They are fabricated slightly larger
than the stud width in order to provide secure attachment top and bottom.
GYPSUM SHEATHING
In order to assure flattest panels with adequate racking
strength, 1/2" thick fire resistant gypsum sheathing is screwed to the steel
stud framing with self tapping screws prior to lath and plaster appl i cation.
Gypsum sheathing has a water resistant gypsum core
encased in specially treated brown water repellent paper on both sides and long
edges. It is not a vapor barrier!
Available 24" wide with V-shaped T & G long edges,
normally applied horizontally with tongue up. Also available 48" wide with
square edges for vertical application.
CASING BEADS (Plaster stops)
Fabricated from 26 gauge galvanized steel, casing beads
are available
in 112", 3/4", 7/8", I" and 1-1/4" sizes to accomodate
different thick- nesses of plaster and finish materials. Best quality panels are
pro- duced when 1-1/4" casing beads are installed to the framework first,
then the sheathing, lath and plaster is installed.
Casing beads are also available on special order in zinc alloy and stainless
steel.
PAPER BACKED, SELF-FURRED METAL LATH
Lath for Portland cement plaster can be expanded metal,
woven wire (chicken wire) or welded wire fabric. All three are available with a
self-furring feature and with factory applied paper backing.
,The building codes allow for the elimination of paper
backing when lath is installed over a solid backing like gypsum sheathing but
best results are achieved when the weather resistant paper is in- cluded.
There are two grades of building paper approved for use
as a weather resistant underlayment for exterior plaster. Both are covered by
Federal Specification UU-B-790, Type 1, Grade B or Grade D. The difference
between the two grades is in the allowable moisture per- meability.
I
FORCES AND STKESSES
The exterior skin of any building is subject to many
different forces, from wind, earthquakes, framing movement, thermal fluctuations
and vibrations. Whenever a force acts on a body, there is an accompanying change
in size or shape of the body. These forces cause the wall materials to bend,
deflect, deform or compress, sometimes to the point of failure. Any material's
ability to withstand these forces depends on the strength, stiffness and method
of installation.
A.
DEFLECTION
Deflection is a typical physical action. It is that
deformation which occurs from bending forces perpendicular to the panel face
Brittle materials like plaster and tile may crack or delaminate
when the matrix deflects as much as 1/360 of the overall
span.
Panelizing Exterior Walls with Steel Studs, Lath,
Portland Cement Plaster and Ceramic Tile
Deflection -in steel stud framed panels can be reduced
several different wayst,
Use larger stud.
(6" stud instead of 4")
Use stud of heavier gauge.
(16 gauge instead of 18 gauge)
Decrease stud spacing.
(24" to 16" or 16" to 19")
Reduce the height of the panel.
B.
RACKING
Racking is a physical action resulting from earthquakes,
framing movement or forces in the direction of the plane of the panel.
Sheathing, lath, wallboard, and other collateral
materials properly attached to studs afford a small degree of racking
resistance. Diagonal bracing welded to every intersecting stud provides the best
values.