never looked so good
basic understanding of working with concrete and color is important
-- but so is having the right tools.
who's ever grunted a slab into place might have trouble believing
that concrete flatwork could become an architectural trend. But
it has. The cost-effective finishes you can produce through patterned,
stained, and textured decorative concrete are limitless. And while
the tools aren't exactly exotic, the techniques and timing are crucial
basic products used to create decorative concrete include texturing
tools, which are mat-type imprinting tools for texturing freshly
placed concrete: admixture, which is color added directly into the
ready-mix: color hardener, which is a dry-shake colored powder broadcast
over wet concrete: and chemical stains, which are liquid penetrating
stains that combine with Cured concrete to produce permanent variegated
or translucent color effects.
basic understanding of working with concrete and color is important-but
so is having the right tools. Having enough of them and understanding
how and when to use them is critical.
Planning and timing are the keys to successful concrete finishes.
From the original pour to the final touches, concrete goes through
a lot of stages, including the curing process. Different tools correspond
to different stages of the hardening process, so you need to understand
good concreting techniques. And you need to provide plenty of tools
to work the concrete and enough workers to operate them.
On a fresh pour, the float is the most important tool. Using the
proper type of float and floating technique to distribute the wet
concrete affects the long-term durability and quality of the material.
Don't rush the finish. Premature surface finishing will result in
a low-quality surface that won't stand up over time. Always use
a wood bull float when the concrete does not include an air-entraining
admixture. If the mix does have an air-entraining admixture in it-which
means you have to use a magnesium bull float-try to keep your float
as flat as possible on the surface.
The objective of floating is to keep the surface open: that allows
the bleed water to evaporate. It you aren't careful floating the
surface. you can make the surface too smooth by float-ing the bleed
water into it, and it won't cure properly. This concept also applies
to hand floats.
can worry about making, a smooth surface later in the curing process,
when you trowel it to a final finish.
decorative projects include accent bands in contrasting colors,
which require the use of smaller hand tools to conform to the size
of the band. The most efficient way to make an accent band is to
use what is commonly called a combination tool. This tool simultaneously
bevels the perimeter edge and creates a groove for the hand border.
Keep in mind that the combination tool conforms to the lines of
your perimeter forms and your band-lines will only be a, straight
as the forms.
you have evenly floated the concrete. leaving no dents or holes.
you can add the color and start working on other decorative elements.
Having hand floats and finishing tools ready in a variety of sizes
will make your job easier -when finishing the bands or other design
elements. Allot enough trowels and other tools for each color, especially
when working with different surface colors, or color hardeners.
Color hardeners are hand-broadcast over the surface of the wet concrete
and must be evenly troweled into the concrete.
takes place when the concrete is well into the hardening process,
but still impressionable enough to take the imprint. As a rule,
you should allow' for enough imprinting tools to span the length
or width of the project plus one additional tool. The additional
tool is sometimes called the stack tool; it starts the second row.
Having too many tools is better than not having enough. A sufficient
number helps ensure that
the entire Stamping process is Successful. Use good quality imprinting
tools that will support your weight so you du not create "bird
baths:' or imperfections, in the pattern.
set of imprinting
tools includes a flexible tool called a floppy. The floppy has the
same pattern as the platform style tools but is made of much softer
polyurethane. enabling it to bend and conform to surface variations.
Floppies come in handy when imprinting three-dimensional surfaces,
such as stairs, or any odd leftover areas not quite covered by the
decorative option is to use texturing skins. These are flexible
pieces of polyurethane that come in different shapes and sizes.
They don't have lines or grout joints, so they only impart texture,
allowing for a more free-flowing pattern. It's a good idea to include
a tamping device in your toolbox to tamp the imprinting tools as
the concrete hardens--although your weight is usually enough to
transfer the pattern.
keep an assortment of chisel sizes handy to touch up the tooling
of the patterned joints. Especially with troweled-in color hardeners
in small areas, such as bands, the joints often get blurred. And
once you have troweled in any desired colors, check all joints and
your edging to make sure you maintain clean lines.
Staining is also gaining popularity as a flatwork finish. Chemical
stains can be applied to pre-existing concrete as well as on freshly
cured surfaces. Some people work with stains as an overall color
application, while others work with them almost like paints, creating
very detailed and intricate designs. You can even make stains that
mimic marble floors.
anything can be used as a staining tool, from spray bottles to sea
sponges to Saran Wrap. I've even seen a designer pour the stain
onto the dried concrete and blow the color in random branch-like
patterns with air. Whatever design tool you choose, it is important
to keep in mind that stain is very caustic and should not come into
direct contact with your skin.
popular decorative technique is installing sandblasting templates
on new or old concrete. The company 3M makes self-adhesive template
products. Their materials can be cut into intricate patterns and
borders and applied to the cured concrete. Whatever area is covered
by the material is protected from the sandblasting, leaving a smooth-troweled
surface. The unprotected area is etched by the sand. The resulting
texture can range from very fine to coarse, depending on the depth
and texture specified by the design.
is commonly used to cut joints into cured concrete, but many designers
are also using saw-cutting as a design tool. When cutting aesthetic
joints, or creating the look of tiles, always mark the concrete
first with a chalkline. A walk-behind saw-cutter is the easiest
way to cut large, straight lines.
freehand forms I suggest a 4-inch handheld grinder with a 1/8-inch
to 1/4-inch-wide diamond-tipped blade. You can sketch the design
in pencil for guidelines, but you really need to be a very accomplished
saw-cutter to go freehand. The Dremel is another popular tool for
adding intricate detail to designs.
Tips for Interiors
Decorative concrete flooring has become very popular for interiors,
from floors to countertops. The tools are essentially the same for
interior and exterior applications, except for one important difference:
Interior equipment should be dustless. Especially with saw-cutting
and sandblasting, there are specific attachments or models for dustless
with the various tools-and knowing how to use them correctly-is
paramount to the success of an architectural concrete project. Don't
forget: Good planning helps ensure a good outcome. Concrete is a
dynamic building material-it won't wait for you to run to the hardware
store to purchase some additional trowels and chisels.
Bob Harris is the director of product training for the L.M.
Scofield Co. He has 18-plus years of experience in the construction
industry and has completed a three-year apprenticeship program for