beater or pounder A tool used to tamp stamps into plastic concrete to create an impression.
hand stamp A small, hand-held blade tool made from cast aluminum or plastic, used to create a pattern in places too small for stamps to fit.
mat A flexible plastic tool used to provide texture and low-profile patterning. The mats can be as large as 5x5 feet.
pattern Lines and curves stamped into a concrete surface.
release A powder or liquid material used to achieve a clean separation between stamps or texture mats and fresh concrete. Additional color highlighting can be produced by adding color to release agents.
skin A small piece of textured plastic skin, even more flexible than a mat for providing texture in small areas that can't be reached with stamps.
stamp A platform tool, usually made of urethane plastic, for making impressions and patterns in fresh concrete. Stamps are approximately 2x2 feet in size. Stamps should be firm enough to support a worker's weight on fresh concrete, and the contractor should have enough of them to reach across the width of a placement.
texturing The process of providing texture to the surface of concrete without a pattern.
adhesive stencil Adheres to concrete and doesn't allow decorative material to get under the stencil.
mylar or clear acetate stencil Used to transfer patterns. Materials can easily get under this type of stencil.
negative weed Removal of the negative field. Therefore, the design itself is masked.
paper or cardboard stencil One-time, one-use stencil material.
positive weed Removal of the positive field. As a result, the design receives the decorative treatment.
weed What is removed from a cut stencil.
Sand Blast Stenciling
blast media The material used for blasting—made from sand or slag products.
negative field The parts of a pattern or design that are blasted into the concrete.
positive field The embossed area where blast material is not allowed to impact the concrete.
resist, buttercut, or adhesive template A plastic, adhesive material 1/16 to 1/8 inch thick that has a pattern cut into it. When the pattern is adhered to the concrete surface, the exposed parts of the pattern allow blast material to etch the concrete.
stencil A template constructed from adhesive material, wood, metal, or plastic. Patterns and designs are cut into the stencil to mask the concrete surface from the sandblast. Patterns can be cut by hand or by computer graphic programs and plotters.
wicking The process whereby blast material tears concrete from underneath the edge of a stencil.
Stencil Patterned Concrete
embed The process of impressing the stencil into the concrete so that the top surface of the stencil matches the top surface of the concrete.
hopper gun An air-driven spray gun with a hopper located close to the spray tip, for holding polymer cement material. Cement is sprayed in a splatter pattern onto the concrete surface.
knock-down The process of lightly troweling and flattening the splatter marks left by the hopper gun. The resulting finish offers both good traction and a pleasing pattern.
stencil Plastic-coated paper, cut to resemble the joints between stone, tile, or brick pavements. Workers place stencils on fresh concrete and broadcast color hardeners on top. Colored patterns can be combined with natural concrete color to create the appearance of mortar joints. Stencils can also be placed on existing concrete slabs and sprayed with polymer cement, using hopper guns.
stencil roller A tool similar to a paint roller, used to embed stencil material into fresh concrete. There are small plastic spikes on the roller.
texture roller A cylindrical tool with a raised texture. It is rolled over both the stencil and the fresh concrete to impart texture on exposed surfaces of the concrete.
chemical, acid etch, or reactive stain A material composed of water, mild acid, and reactive penetrating metallic salts that create transparent, permanent colors in concrete. A reaction between the metallic salts and the “free limes” or calcium hydroxide in the concrete causes a permanent metallic hydroxide color reaction.
dyes Non-reactive penetrating salts that provide translucent coloration. Once mixed, dyes stay in solution. They can be used in addition to chemical stains.
patina Chemicals that, when applied over the top of chemical stains, create the natural effect of weathering. Patina chemicals add to coloration possibilities.
RAC An acronym for Reactive Acid Chemical concrete stain.
resist Products applied to concrete surfaces to prevent stains from penetrating.
solvent stain Fine grinds of pigment, driven by a solvent, that penetrate a limited depth into concrete surfaces.
spotting Arranging for small concentrations of color on concrete surfaces. Spotting agents include dry metallic salt compounds, liquids, granules, or powders. They are activated by water or acid. Concrete must be wet in order for them to work.
tints Opaque colored, nonpenetrating pigment sometimes used in combination with chemical stain treatments. Tints don't stay in solution and only coat the surface of concrete. They are ethylene-glycol-based—sometimes referred to as “universal tints”—and can be used in solvent or water-based materials.
variegation The multicolored effect that results from placing chemical stains on concrete. This effect can be enhanced by creatively adding different stain colors to the concrete or by applying one color in special ways.
water-based stain Nonpenetrating pigments added to color concrete surfaces.
working time The amount of time that a stain is in contact with wet concrete before it dries out.
Diamond Polished Concrete
coarse grinding Concrete polished up to a 150-grit finish.
densifiers Chemically reactive agents (silicates, siliconates, or silicate/siliconate blends) applied to concrete finishes between the coarse grinding and polished grinding steps, to harden and densify the surface, making a higher level of polishing possible.
grit finish The last grit size used in a polishing sequence. The number is the size of the grinding grit in microns.
honed finish A highly polished surface —a finish that exceeds 1000 grit.
metal bonded diamonds Diamonds embedded in a metal matrix designed to wear away during the grinding process and expose new diamond-cutting surfaces. The hardness of the metal depends on the material being cut. Metal bond diamonds are used for coarse grinding steps.
planetary head Machinery that has small grinding heads spinning within a large diameter rotating head, randomizing the diamond cutting pattern, making very flat grinding possible with decreased operator error.
polished concrete finish Multi-grit grinding procedure that creates a bright sheen. These finishes start at 150 grit and go to 3000 grit.
resin bonded diamonds Diamonds bonded in phenolic resins, used to create high-grit finishes. They are manufactured for either wet or dry polishing.
Artificial Rock Work
black wash When rockwork is colored after it's installed, a mix of black colored stain and water is frequently applied as the final step. It brings the other colors together and provides an aged quality to the work.
carving Cutting and tooling fresh concrete into rock shapes.
embossing The process of joining GFRC castings in a way that makes a rock formation look natural.
embossing skin Flexible latex rubber or urethane plastic mats that workers use to provide rock texture on fresh concrete shapes.
flecking Coloring rockwork to simulate granite or other multicolored rock finishes.
GFRC rockwork Precast glass-fiber-reinforced concrete panels of rock shapes and textures. Panels are assembled in random fashion on the jobsite to create realistic rock forms.
granite, basalt, weathered, or sandstone finish The primary rock finishes.
gunite and shotcrete Gunite is shooting a mix of portland cement and sand with a small amount of water at high velocity onto the work area. Shotcrete involves shooting ready-mixed concrete at lower velocity onto the work area. Both methods are used for hand carved rockwork applications.
hog ring A staple-like device used for securing burlap to chicken wire for hand-carved applications.
plastic portland Portland cement with materials added to enhance properties such as setting time, workability, water retention, and durability. It's often used for embossing and for hand-carving rock shapes and is sold as type M or S cement.
polymer rock Artificial rockwork constructed with polymer concrete. Rough rock shapes are usually constructed with polystyrene foam first, with buildups of polymer cement to add the fine detail.
positive rock or hand carved A method for installing artificial rockwork in place. The process starts by building a rebar frame, draping it with chicken wire and burlap, spraying shotcrete or gunite concrete onto the frame, and hand-carving rock shapes. Concrete can be added afterwards to build more detail.
sheer descents, cascade, grotto Types of rock formations reproduced in artificial rockwork.
solid fill The process of filling behind rockwork with concrete, either to add strength or to give the rockwork a solid sound when people tap on it.
Sealers and Coatings
breathable sealers As the membrane is formed, microscopic pores develop that allow water vapor, but not liquid water, to pass through the coating. Acrylic polymers are the principle resins with this property.
penetrating Unlike membrane-forming materials, penetrating sealers leave little trace of their presence after application. Most are silicone-based materials, which react with the calcium hydroxide in concrete to produce hard, cement-like materials which block capillary pores in the concrete.
solvent-based Works in the same way as water-based coatings except that the vehicle carrying the resin is a solvent, which, upon application, evaporates into the air.
water-based Either protective or decorative membrane-forming coatings that use water as the vehicle for application. They can be acrylic, epoxy, urethane sealers, or combinations.
integral Using the aggregate in the concrete mix as the rock to be exposed. With this approach, mixes typically have more aggregate—often decorative stones.
seeded The process of broadcasting decorative stones on the surface of freshly placed concrete and later exposing them.
surface retarder Material sprayed onto the surface of fresh concrete to delay its initial set. When the matrix of a slab is hard, the cement paste on the surface can be washed off without dislodging the aggregate.
adhesive bonding Attaching formliners to a wall form through the use of adhesives that permanently join them to the wall form.
cutables Liners made from inexpensive materials. They are cut into pieces to fit in small places.
gaskets Formliners designed to surround brick or tiles in position. The gasket forms the mortar joint between units and must also keep cement paste from reaching the face of the units.
hollow liners Vacuformed patterns using sheet plastic materials that have air spaces on the backside of the liner. Lateral concrete pressures must not exceed the ability of the liner to resist them.
interlocking patterns Patterns that provide for continuous pattern lines past the limits of a formliner.
limited use Liners made with inexpensive materials for one or two uses.
mechanical bonding Attaching formliners to a wall form using bolts, screws, or other mechanical means.
negative face The formliner surface.
positive face The formlined concrete surface.
rustication Lines formed with wood or plastic on wall forms to provide architectural features.
vacuform The process of making formliners by heating plastic sheet goods and pulling them into a mold by using vacuum.
arcuate A cut that bends or curves like a bow or an arch.
engraving The process of forming patterns, designs, and logos by cutting, grinding, routing, or using other means to create 3-dimensional surfaces in concrete.
freehand cutting Using hand-held concrete cutting tools, such as grinders, to produce patterns or designs in a concrete surface.
kerf A cut made by a saw, grinder, or router in a concrete surface.
long cuts A continuous kerf line—straight, curved or any combination of the two.
short cuts Kerfs beginning and ending on long cuts.
tracked cutting Method of mechanically controlling a concrete cutting device to produce patterns in a concrete surface.
concrete surface profile (CSP) The preparation of the existing concrete surface to receive overlay cement.
gauge rake A tool resembling a rake that has height adjustments on it, allowing workers to easily place the desired thickness of polymer cement on a slab.
moisture vapor emission rate (MVER) The rate of flow of water vapor through concrete.
self-leveling overlay Overlay materials typically applied with gauge rakes to provide the correct thickness and then self level. Highly productive placements are possible with these materials.
skim coat Polymer cement applied approximately 1/16 inch thick by trowel.
smoother trowel A large trowel with a long wooden handle that allows the finisher to stand up. Self-leveling overlays are troweled with this tool within 5 minutes of application to complete the finishing process.
stampable overlay An overlay cement designed to have patterns stamped into it. The thickness of the overlay is usually determined by the profile thickness of the stamp.
trowel-down or micro-topping overlay Overlay cement that is formulated for applications from about 3/16 inch down to feather edge. It is applied by trowel and often the trowel marks become part of the appeal in the finished look.