Arban & Carosi offers a wide variety of architectural precast concrete finishes ranging from surface textures to cladding elements. The precast finish of a project is an important decision in the overall appearance and feel of the building. We work with architects throughout the Mid-Atlantic area in aiding and preparing samples for upcoming projects.
Arban & Carosi offers an assortment of colors and finishes ranging from a white acid-etch, brown sandblast, to a black water-wash.
An acid-etch finish is a lighter finish where the cement paste and sand are the predominate element on the surface. This is achieved by spraying muriatic-acid on the panel surface to expose the sand. An acid-etch finish is often used to achieve the look of limestone or other smooth stone as it results in a “sugar cube” like texture. Today, almost 70% of our work is acid-etched.
A sandblast finish is typically a rougher finish that exposes the sand and stone. This is achieved by abrasively sandblasting the cement-paste and some sand off the surface of the panel to expose the remaining sand and stone. A sandblast finish is often used to achieve contrast to an acid-etch element or to simulate granite and other rougher natural stones.
A water-wash finish is the roughest finish and exposes mostly all stone on the surface of the panels. This is achieved by applying a “retarder paint” to the mold surface which prevents the sand and cement on the face from bonding. The panel then gets washed down with water causing the sand and cement to fall off the face exposing the stone to the surface. The main difference between a water-wash and sandblast finish is that the stone remain crisp and clean (un-bruised as there is no abrasion as in sandblasting). A water-wash finish is often used to achieve contrast to an acid-etch element or to simulate granite or other rougher natural stones.
Color variations can be achieved either with the inclusion of pigment, sand, stone or all in the mix design.
The use of pigments is the most frequent way to create colors in a precast panel. The pigments blend (mainly) with the cement paste in the mix to provide a baseline color of the panel. Pigment colors are offered in almost every color of the rainbow, though the natural colors work best. Additive pigment dosages can range from 3 ounces to up to 50 pounds per cubic yard of concrete.
Sands can also be used to add color to a precast panel. The use of sand, while limited in color range, is a great way to add color or “life” to the panel. We also often suggest using closely colored sand when making a mix with a heavily-dosed pigment amount as it allows to ensure better color control. Colored stone can also be used to add color if used in a heavy sandblast or water-wash texture.
Formliner and Cladding Elements
Formliner and material-cladding are also very popular ways to finish an architectural precast panel. In both applications, material is laid in the mold and concrete is poured on top of it.
A formliner finish is typically a pattern formed in the surface of the panel by laying a reverse-pattern form (a formliner) in the mold. The pattern can be anything that can be modeled, through it is usually a standard typical pattern (like ribs, dentals, detail lines or waves). Formliners can also be used for odd patterns, stone textures, wood textures, and really - anything imaginable.
Material Cladding, including brick, thin-brick, stone, terracotta and tile, has become much more popular in the last ten years.
Brick-Cladding can be done with either, thin-brick (more like a tile-brick) or with a soap-brick (a real brick cut in half). There is a wide variety of colors and textures offered in both thin-bricks (in TBX tolerances), and soap-bricks (in FBX tolerances). Thin-brick panels are much more cost-efficient as the material is less expensive, and the installation labor is low. The soap-brick panels provide a more natural brick appearance, but costs are higher due to the material and labor installation. For brick selections see United Wall Systems or Potomac Valley Brick.
Stone-clad panels are also very popular, particularly in taller buildings. The stone pieces are installed in the face of the panel with a mechanical anchor and separated by a bond breaker. Granite, limestone and marble are the most commonly used cladding elements in precast.
Terracotta and Tile clad panels are increasingly being used on buildings instead of the mason installed application due to the speed of construction and cost savings. Both products are installed in a similar manner to the thin-brick. A wide variety of both terracotta and tile are offered that are acceptable in precast application.