Let Good Looks Shine Through
By Robin Suttell
wants to remain a dullard forever. Concrete is no exception. Blandly gray
to the eye but reliable in use, traditionally it has been relegated to
basements, garages, driveways and walkways as a functional surface, not
a decorative one. Yet, concrete is coming into its own. Today, contractors
and developers are specifying and installing intricately textured cast
concrete into foyers, lobbies, garden pathways, and even countertops.
But what about the cubic yards of already-installed humble gray matter?
Are these surfaces doomed to remain forever mundane?
are, you'll have clients who will want to update their existing concrete
surfaces from functional to fashionable. With the help of a high-quality
concrete stain or refinishing product and some creativity, you can now
engineer a complete makeover of the dull kid on the block. This product
category offers a wealth of opportunities for contractors.
Skinny on Stains
In the past, people seeking style have often opted to paint concrete surfaces.
Particularly in the 1950s and `60s, patios, garages and basement recreation
rooms sported bright-colored paint to disguise fundamentally functional
surfaces. But paint, as you know, can sometimes need lots of attention.
Paint sits atop the concrete and covers the natural surface texture. Since
the paint does not penetrate the concrete surface, it can eventually fail
because of the substrate's inherent moisture. In fact, SherwinWilliams'
experts report that concrete's moisture content rarely dips below 15 percent,
even in existing installations.
Thus, as moisture attempts to escape the opaque coating, it forces cracks,
peeling and blistering in the coating film. The traditional definition
of a stain is a "transparent or semi-transparent solution or suspension
of color matter in a vehicle designed to color a surface by penetration
without hiding it." And for this reason, today's concrete stains
offer some definite aesthetic and performance benefits. Concrete stains
penetrate the porous surface and add color without hiding the concrete's
natural texture. These penetrating coatings shift with the concrete and
allow the substrate to breathe.
"A painted surface is just that - an opaque painted surface,"
says Bill Shorey of Spec-West, a Sacramento, CA-based concrete products
distributor. "It gives you a specific hue or color."
"Staining doesn't deliver a specific color because it is a reactionary
process," he explains. "The concrete itself actually gives you
the final look. Depending on how old the concrete is and the condition
it is in when you start out can make a lot of difference Ti The stain
can enhance and intensify tile discoloration and marks in the concrete
.A lot of people want that variegated 'Old World' look."
Shorey uses wood stain as a comparison Both concrete and wood are highly
porous surfaces. As a result, penetrating stains don't cover the substrate
uniformly. Instead the coatings infiltrate the substrate's pores and almost
literally color the inner surface, as well as the outside one.
"If you have an unblemished surface with a good grain you can intensify
the grain," Shorey explains. "Concrete isn't just gray. You
have high and lows, lights and darks, stains and black marks. When you
stain it, the stain accents those different imperfections unless you put
down a topcoat. It's not a smooth, unbroken finish."
Clean air regulations and a concern for the environment have brought about
a new generation of improved water-based acrylic stains. These products
are easy to apply and they clean up with soap and water. They have low
odor and also have a low volatile organic compound (VOC) content, a key
requirement for states with strict emissions regulations like Arizona
Popular water-based concrete stains include Safety Stain II from Flex
Art Company, Mason's Select Transparent Concrete Stain from Duckback Products
and the H&CT system of concrete care products from The Sherwin-Williams
stains in these lines are typically composed of acrylic resins in a water
base. This formulation allows the stains to penetrate deeply into the
concrete surface and adhere to the concrete to bring out color.
Another option, polymer refinishing systems - such as Concrete Solution's
Ultra Surface Concrete Polymer change the chemistry of regular concrete,
causing mixtures of cement, sand, water and the polymer to adhere or bond
tenaciously to an existing surface. Similarly, Micro-Top from Bomanite,
a combination of liquid polymer and a
colored powder, can be applied to create surface uniformity or be blended
to create an eye-catching variegation.
Limitless color combinations and graphic designs can be used to transform
existing concrete and other materials into art forms without affecting
surrounding materials and fixtures. Most water-based stains and overlay
systems come in at least 40 colors, as well as custom colors, expanding
color choices immensely over traditional acid or chemical stains, which
come in a range of about eight earthtone-inspired shades.
acid or chemical stains, Shorey says, yield the best-variegated finish
with a nice wash of color. However, as Luposello notes, such stains can
be challenging to use and offer less protection than water-based counterparts.
Nevertheless, acid/chemical stains have many fans because of the stylish
effects they bring to concrete surfaces. They do not have as deep of a
penetration as the water-based products, but instead derive their coloration
through chemical reactions between their cot components and the aggregate
to which they are being applied. Because of various environmental and
air quality issues, today's acid and chemical stains generally contain
some sort of water component.
Acid stains, such as Blush Tone from Brickform/Rafco Products, Lithochrome
Chemstain in from L. M. Scofield Co., Rare Earth Stains, Bomanite Chemical
Stain, ChlorStain from SuperStone, Kemiko Concrete Stain, and QC Patina,
to name a few, chemically color concrete surfaces by combining the metallic
ions with particles in the concrete to form oxides. The acid in the stains
lightly etch and penetrate existing concrete, allowing the ions to form
permanent insoluble chemical precipitates that remain in the a concrete's
Repair, Prepare and Refinish
concrete surface that is to be refinished, whether it is a floor, walkway
or even a countertop must be clean ; and porous in order to ensure,, c
good topcoat integrity As in any job, the age-old mantra of good surface
preparation is key.
First, clean the concrete to remove any grease, oil, paint or other contaminant
that would inhibit the penetration of the stain. Then test the surface
to see if it needs to be "etched" or sanded in order to permit
the coating to apply easily. Luposello suggests feeling the surface and
comparing it to a Piece of 120-grit sandpaper. "If it feels the same,
then it's OK," he advises `'1f not, the surface needs to be 'etched.'"
If you're using a water-based product, some experts recommend using use
a 10:1 Solution of muriatic acid and water or a similar product. This
process, called acid etching, opens the surface of the concrete to allow
good adhesion and penetration. Rinse thoroughly several times and allow
the surface to dry completely.
Other professionals advise against acid etching and instead suggest using
one of the many commercial concrete preparation cleaners or strippers
on the market. These products are reported to be milder but do a similar
job to etching. The preparations are designed to remove dirt, grease and
oil from the surface to be stained.
If you're coating with a chemical stain, do not use muriatic acid. The
purpose of using muriatic acid is to get down to clean, new cement. It
will "eat" away the cement and leave the aggregate - that is,
the sand and stone mixed with the cement to make concrete. Because of
the presence of the muriatic acid, the acid stain will not react with
this treated surface. And, the aggregate will not take the color. Shorey
instead recommends sanding the surface to achieve the textured finish
needed to accept the chemical stain. He also likes sanding for water-based
stains, he says.
For either acid stains or waterborne products, proper preparation for
the look you want to achieve may include pebble blasting or powerwashing
to ensure a clean finish. And, again, don't forget the critical role that
moisture can play, experts urge. "The concrete must be completely
dry-not just the surface," Luposello says. "If moisture is below
the surface and gets trapped below the coating it will event eventually
come up, thereby ruining the job. We recommend a 24-hour drying period
between preparation and application of the first coat."
Efflorescence - the white residue caused by surfacing of concrete's inherent
salts - can be removed by a light sanding or by using a commercial masonry
cleansing agent, according to the Portland Cement Association. The trade
group also notes that latiance, a fine, powder-like material sometimes
found on the surface of hardened concrete, should be removed by a steel
scraping tool, acid etching or sandblasting/sanding, depending upon the
kind of coating you will be using.
Good to Know
Application and finishing recommendations vary from brand to brand, so
it's important to follow the manufacturer's label instructions or tech
data sheets to ensure your job is the best it can be.
As a rule, however, most water-based concrete stains look best with a
twocoat application. The first coat usually will penetrate and seal the
concrete but not show a great deal of color. A thin second coat, applied
12 to 24 hours later over a dry surface, will bring out most of the desired
color. A third coat can intensify the color even further.
Some manufacturers recommend spray applying the first coat, using either
a pump or airless sprayer. Initial application with a brush, roller or
pad applicator may result in lapping because the concrete may absorb the
first coat faster than these types of application tools can apply the
Wait at least 2 4 hours to walk on floor surfaces. And, for exterior surfaces
such as driveways, allow surface to dry for at least seven days before
running vehicles across it. Acrylic stains are often prone to tire marking,
and some vehicle tire brands contain chemicals harmful to coating products.
Thus, it's not uncommon for the finish coat to lift off the surface after
a vehicle has sat on it for several hours.
Polymer overlay systems generally can he Applied with a squeegee or a
trowel on the surface area at a thickness of approximately 20 mils, depending
on the manufacturer These systems can give an existing concrete surface
not only a new, fashionable color, but they also can be worked into decorative
textures with tools or stamps. Always consult the product label for the
manufacturer’s directions and product usage recommendations.
Because chemical stains contain hydrochloric acid, always use gloves and
a rubber apron when applying acid stains. And if you're working inside
or have respiratory problems, don't forget to wear a respirator or mask.
Two coats of acid stain deliver the best results. Whether you spray or
brush depends on the manufacturer's recommendation. Once stain is on the
surface, you must scrub it in with a brush as soon as it touches the concrete.
Shorey suggests waiting a minimum of four hours, or until the stain is
dry, before re-coating When applied, acid stains will fizz. This is due
to the chemical reaction with the concrete. Continue spreading the stain
in a circular or figure-eight motion until the fizzing action ceases.
At least four hours after the final application, the surface must be scrubbed
and rinsed clean.
Due to the hazardous content of the stain, all residues, runoff, cleaning
water and absorbent materials must be discarded and disposed of in accordance
with applicable state, local and federal regulations.
Both concrete stain manufacturers and experienced contractors say a routine
maintenance schedule for all colored concrete is key to preserving a top-quality
appearance. Maintenance will vary depending on a number of factors, including
intensity of traffic, UV exposure, geographic location, and weather conditions.
Interior residential applications, for example, require less cleaning
and maintenance than larger scale commercial projects.
The first step of this plan is sealing the surface following application
and drying of the stain. In most cases, experts recommend applying two
coats of an acrylic sealer. Products of this type will seal the surface,
enhance the color, resist staining from foreign matter, as well as provide
easy cleaning and maintenance. Be sure to follow manufacturer's application
instructions. Acrylic sealers, however, will not provide a high-gloss
surface or prevent scuff marks from shoe soles as a commercial wax will
While some contractors apply a coat of urethane over the sealer, Shorey
says a wax coating provides an excellent final touch. "I recommend
using a good maintenance contractor to apply a wax coat," Shorey
says. "Have that person apply sealer and then put down three to four
coats of wax."
In general, the need for professional maintenance ranges from 12 to 24
months, depending on foot traffic. Maintenance wax coats should be applied
periodically to assure the desired gloss level. Your stain and sealer
manufacturer can provide you with the names of qualified maintenance contractors
in vour area.
And, keep in mind that each sealer brand will likely affect the stain
coat's color differently. Consequently, it's important to include the
sealant step in the test sample you prepare for your clients. "You
don't want to have any surprises at the end of the job," Shorey says.
Job Site Troubleshooting
Both decorative concrete and coatings experts say they cannot stress enough
the unpredictability of concrete as a substrate. "A contractor must
always test the stain/sealer in an inconspicuous spot to ensure that the
desired results will be achieved before full application," Luposello
But sometimes, even testing isn't fail-safe. Concrete can simply be a
fickle substrate. Shorey recalls a time when he once sold a dark acid
stain to a contractor to cover a coffee shop floor. The contractor had
done test samples in an out-of-the-way area, which resulted in a rich
dark brown shade that the owner loved. After staining the entire floor,
the contractor called Shorey with a problem: The entire job had come out
jet black and the coffee shop owner could not live with it. The contractor,
Shorey recalls, was desperate for a solution.
"Having known from experience that a diluted muriatic acid wash would
lighten the acid, I offered this as an option to the contractor,"
he says. Adding, "if it did not work then the next option would be
to re-sand the floor, put down an overlay and/or maybe both, depending
on unpredictable results when using acid stain on old concrete."
The contractor called Shorey several days later. "He could not thank
me enough," Shorey says. "After being coated with a mild (20:
1) muriatic acid solution, the floor had come out a wonderful chocolate
brown with nice mottling."
Concrete dyes can also solve application problems. Shorey recommends using
such a product if the finished stain job has areas that did not take stain
at all. For example, a 1,500square-foot floor stained dark green has one-or
two-foot-square areas that are still pretty much bare concrete.
"It can happen with old concrete, and it happens often, even if you've
sanded well," Shorey says. "You can fix it by mixing the dye
with denatured alcohol and fogging it in over the gray area. It is transparent
and mottles in with the stain, making it look like stain... but it's not."
Whether you're using acid stains or water-based formulations, enhancing
existing concrete surfaces requires experimentation, skill and practice
to discover the multitude of colors and patterns that can be achieved.
While applying concrete stains at first might be daunting, learning this
skill can open new doors for your business and to your clients.
A posting on the Decorative Concrete Network (www.decorative-concrete.net)
forum archives perhaps sums up the benefits of using a high-quality concrete
stain: "The multitude of desirable, lasting, decorative effects which
are achieved by the use of stain (in lieu of paint) make for a much wiser
investment, time, money, wear resistance, and lasting eye-appeal!"