| Tilt-Up Concrete
There are two main types of panel systems used for concrete
walls; precast concrete and tilt-up
concrete gets its name from the manner in which construction occurs:
by lifting (or tilting) panels with a crane to form the walls of
buildings. Panels can be produced in many shapes and sizes, including
flat and curved sections. Concrete placement is fast and easy because
it is done on the ground. Floor surfaces serve as casting beds or
sometimes separate casting beds are built. Panels can be stacked
on top of each other if space is limited. Because the panels are
cast on site, their size is not limited by trucking considerations.
Panels are typically rather large in size so that there are relatively
few joints in buildings.
The tilt-up industry notes that tilt-up structures are built at
reasonable cost, require little maintenance, and provide long term
durability and speed of construction with minimal capital investment.
Panels usually serve as structure and finish
and can be insulated as needed for energy efficiency.
Although this industry started more than 100 years ago, its popularity
increased markedly following the 1980 introduction of an American
Concrete Institute committee (ACI 551) dedicated to it, and the
formation of the Tilt-Up Concrete Association in 1986. More recently,
advancements in design flexibility, premium finishes, better insulation
techniques, and the ability to build smaller structures more economically
have increased the appeal of tilt-up. Contractors specializing in
tilt-up are available throughout the U.S.
The following points describe tilt-up concrete panels for low-rise
More information on precast is available from the Tilt-up
Concrete Association. From codes and standards development to
education and marketing, this organization supports the success
of tilt-up concrete.
Tilt-up construction is rapid and economical. While it became popular
for large buildings with simple floor plans (“big box construction”),
new techniques have expanded the market to improve the design flexibility,
making it suitable for small buildings and ones that have more involved
layouts. The key to success is planning. Now schools, retail, commercial
and civic projects, religious structures, and residences are common
Contractors appreciate that much of the work is done at ground level
and is fast and efficient, with repetition providing time savings.
Making tilt-up concrete panels is essentially like casting slabs
instead of walls. Formwork placement is faster and simpler, including
block-outs for door and window openings. Panels are cast on site
and if space is tight, they can be stack-cast (up to 4 high is common)
to minimize site disturbance.
|Finishing concrete on a tilt-up panel following
For owners, the appeal of tilt-up is durability and the strength
to resist disasters, water, and insects. The heavy mass and large
panel size also leads to good energy efficiency and sound performance
due to thermal mass and airtight enclosures.
Uninsulated panels are typically 7 to 12 in. thick. Insulated panels
are sandwich-type construction. The outer face is 2 to 3 in. thick,
the insulation is 2 to 6 in. thick, and the inner layer is the structural
portion of the wall with a thickness similar to uninsulated panels.
Connectors are inserted through the insulation to tie the two concrete
Advancements in lifting inserts means that there are fewer limitations
on panel size: 50 ft tall panels are common. The floor footprint
may be one constraint on size. And since panels must be lifted into
place by a crane, their weight versus crane capacity is another
limiting factor and the crane should have a safety margin of 3 to
1 for this purpose. But panels do not have to be shipped to a site
by truck, so this is not a limitation on size.
Manufacturing and Physical Properties
The foundation and floor (or casting) slab should be prepared for
concrete placement. Formwork is commonly 2 x lumber but may be reusable
plastic or metal. Reinforcement is conventional steel used in other
concrete work. Lift inserts, weld plates, and other hardware are
all termed “embeds” and are placed in advance of concrete.
Bondbreakers are used to coat the casting slab to facilitate lifting
panels. If the lifting crane will sit on a portion of the slab,
its thickness may need to be increased more than the building would
Concrete is commonly ordered from a ready-mix producer. Mixes may
be specified to have high strength or early strength to meet the
project needs. Concrete can be placed directly from the truck chute
or by pump for more precise placement. It is consolidated, trowel
finished, and cured.
|Troweling concrete on a tilt-up panel
||Applying a curing compound to a tilt-up concrete panel
Tilt-up is not enclosed as the panels are being cast, so cold weather
concreting procedures may apply. Fortunately, it is fairly easy
to protect at-grade casting from temperature extremes.
Installation, Connections, and
Following face-down casting, panels are installed by lifting off
the slab and attaching to the foundation/slab. The combination of
dowels from the slab and attachment to adjacent panels provides
the structural integrity of the building. During placement, panels
are braced until they are all tied together to make the walls. Operations
are scheduled for lifting the panels in quick succession. Connections
that were cast into the concrete allow panels to be welded together.
Then vertical joints are filled with sealants.
|Tilt-up wall panel is attached to the concrete slab
||Tilt-up wall panels are braced in position
Architectural concrete treatments add rich detail and surface appearance
to panels. Rustications and reveals can create the appearance of
various panel sizes and shadow lines. Finishes and panel configurations
have seen much development in recent years so that these panels
offer the same versatility as other concrete wall systems. Common
finishes include colored concrete, exposed aggregate, and form liner
textures. Facing mixes can make any of these finishes more economical
by placing the special concrete mixture in the outer 1 or 2 in.
of the panel’s face. Special inserts are available to create
thin brick or thin block masonry surfaces. Alternately, the surface
can be painted or plastered with a stucco texture, although these
finishes may require periodic maintenance unnecessary with the cast-in
|A white cement facing mix provides an architectural
Casting techniques have advanced enough so that it is now possible
to cast curved panels. This requires special formwork to be built
on the ground, but following the first casting, these can be stacked
like flat panels if necessary.
Sustainability and Energy
Tilt-up panels can be solid concrete, or they may be sandwich-type
construction. Insulation can be incorporated into tilt-up to provide
energy efficient construction with hard exterior wall surfaces.
It is common to use extruded polystyrene at 2 to 6 in. thick. Walls
can range from R-values of about 2 for uninsulated panels up to
about 32 for walls containing thicker layers of insulation. As building
codes require greater energy efficiency, the thickness of insulation
increases. But like all concrete systems, tilt-up offers high thermal
mass, and airtight construction. The panelization also means fewer
joints and reduced air infiltration.
Energy performance is an important part of tilt-up’s environmental
friendliness, but that’s not all it has to offer. All the
other aspects of sustainability that apply to any type of concrete
construction apply to tilt-up. There is potential for recycled content
in tilt-up concrete. Wall panels can be demolished and the concrete
recycled at the end of its life. It’s locally produced. It
is durable and low maintenance.
Tilt-up construction is covered by the International Building
Code (IBC) in the reinforced concrete section. It is usually
designed by a licensed structural engineer. Tilt-up is not addressed
in the International Residential Code (IRC). The Tilt-Up
Concrete Association (TCA) has design guides available. ACI publishes
the Design Guide for Tilt-Up Concrete Panels, ACI 551.2R-10,
which presents information to expand on the provision of ACI 318
to make it more specific to tilt-up construction.
Tilt-up construction was traditionally most economical for larger
panel sizes and bigger buildings. Advancements and planning have
made it more cost competitive even for smaller sized buildings,
in the 5000-sq ft range. For single-family residential, it can be
economical for subdivision development where several buildings are
constructed at one time. Both repetition and economies of scale
can make tilt-up a time and money saver.
Small Envelopes, Big Results: Single-Family
construction gained popularity for large, simple buildings because
the method is fast and efficient, advantages that are important
in this market. Yet given the right conditions, tilt-up can also
be an efficient building method for even the most modestly sized
single-family construction. The availability of smaller cranes has
helped. And making good use of the lifting equipment is important,
too, as can be done in planned communities where many buildings
are built in succession. The prototype home described here is based
on insulated tilt-up wall and ceiling panels.
In size, scale, and design, the home is modest. Its design almost
has a southwest feel to it, but it’s easy to imagine how its
appearance could be adapted to a wide variety of architectural styles,
from traditional to contemporary. The floor area is 1754 sq ft and
the simple, rectangular plan is suited to flat wall sections. Just
30 panels were required to create the entire structure, including
a small front courtyard that adds interest to the layout. Panels
vary in size, with the tallest being 18 ft, the widest 34 ft 8 in.,
and the largest 324 sq ft. Maximum panel weight is 32,450 lb.
floor of the home is a slab-on-grade, which, as usual for tilt-up
construction, serves as the casting bed for the wall panels. Wall
and roof members are sandwich-type construction with integral insulation.
Two concrete facing panels are connected through their foam core
using fiber composite connectors. This provides excellent energy
performance because there is no thermal bridging. The structure
is strong, solid, and resistant to all kinds of forces, including
high winds and impact—for outstanding durability. Exterior
finishes can be as simple as, in this case, a light stucco texturing,
or more detailed. Common decorative
techniques for tilt-up include form liner textures and colors
via paints, stains, or integral colors.
Although it could have been built anywhere, this home is located
in Jordan, a country with a need for modern housing for its military
and government agencies. The model has received considerable attention
from high-ranking government officials there. As yet another testament
of the ease of this method of construction, the contractor was able
to work through the challenging language barrier, providing supervision
and training to local semi-skilled carpenters and laborers, teaching
them how to place and finish concrete, form and place panels, and
erect and brace the final product.
Recreate Historic Charm
Shelmore Village, the owner needed to create a design with flexible
live/work spaces– functional for living space, office, and
also retail. Using just 3 layouts, designers created first-level
floor plans with inviting storefronts and two floors of comfortable
and private residential above—41 units in all. But the owner
also wanted each unit to have a sense of individuality similar to
the downtown Charleston Business District.
Although the owner had no experience with tilt-up,
they selected it with help from the design/build contractor as a
cost effective way to construct affordable housing. Beyond the structural
solution, tilt-up concrete also offered premium performance of seismic
load resistance, firewalls between units, which also act as sound
barriers, high durability and low maintenance, and speed of delivery.
The confined site of less than 4 acres required significant amounts
of stacking panels—some up to 5 high—and detailed coordination
of forming, pouring, finishing, and erection. The tallest panel
is 34 ft-1 in. high and the largest 715 sq ft. Due to the number
and size of panels required to produce 9 three-story buildings,
construction was staged to lift some panels and then reuse the casting
Tilt-up gained popularity in large, simple buildings, the so-called
“big-box retail” stores that frequently have square
or rectangular footprints and not much ornamentation. But advancements
in tilt-up now allow for more complex building layouts and improved
architectural treatments that increase its appeal for a wider range
of applications. Many of those techniques were used at Shelmore
Village. In this case, designers were tasked with recreating the
charm of Historic Charleston – preserving the aesthetically
pleasing nature of the late 17th and early 18th century architecture
– but at an affordable cost. They achieved this by varying
the roof line and building set-backs, exterior materials, and other
external finishes and accents. Combinations of brick, clapboard,
stucco and EIFS, and concrete exterior give a varied street appearance
that disguises the underlying solid concrete walls. Other finish
details include entrance canopies, wrought iron railings and finishes,
shutters and circular window openings, and multi-level porches.
The result is affordable housing with details found on fine custom
The listing of organizations and information resources constitutes
neither an endorsement nor recommendation by the Portland Cement
Association (PCA). PCA disclaims any and all responsibility for
the selection of organizations listed and the products they represent.
PCA also assumes no responsibility for errors and omissions in this
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