Decorative concrete, stainable self-levelers and wear surface toppings are a potential source of untapped revenue for commercial flooring contractors and installers. Building off our coverage in the October/November 2013 issue (“How to Work with Decorative Concrete”), we asked three manufacturers to share their views on preparing and installing these products.
Ardex Americas. Patrick Cunningham, technical service consultant, polished and decorative concrete, said prepping an existing slab for a decorative treatment versus prepping a new slab requires different steps. For an existing slab, “the installation surface should be evaluated to determine existing slab conditions and the resulting aesthetic affect that may be incurred.” He said factors including trench repairs, patching and existing penetrated stains will impact a decorative application on an existing slab.
On the other hand, “preparations for a new self-leveling topping require a slab be evaluated for viability of strength. Mechanical cleaning, such as shot blasting, is advised. Once cleaned, existing crack repair and primers are employed,” he noted.
All proper precautions should be taken whether choosing a stain (which is generally reactive) or a dye (which is non-reactive and penetrates into the pores of the concrete). “Be sure to read all available technical and safety data sheets,” Cunningham said, “and always be mindful of any regulatory concerns of your actions.”
Imperative to a successful decorative concrete installation is the ability to enclose and acclimate the jobsite. “Moisture emissions from a concrete slab will affect selected coatings that do not have the capability to accept excessive moisture,” he stated. “Testing of the emissions must occur, and manufacturer recommendations for maximum concrete moisture emissions must be observed. All efforts should be made to maintain jobsite control and reduce the possibility of topical contamination on the installed decorative application.”
Installers and contractors also might not be accustomed to the level of cracking that can occur naturally in these types of projects. “While all efforts can be taken to minimize reflective cracking in a self-leveling decorative topping, the use of epoxy primers and crack repair products cannot ensure cracking will not take place. Self-leveling decorative toppings can be saw-cut, stenciled and mottled with colorant to reduce the observance of reflective cracking.”
Laticrete. Dean Cunningham, technical service supervisor, ventures and projects, also said controlling site conditions is vital to a successful installation. “Site conditions for decorative self-leveling cement would be 40-90 degrees Fahrenheit during the installation and curing time, protected from direct sunlight, rain, wind, construction traffic and debris. Decorative concrete is very sensitive to ambient conditions and construction dust during installation. The area should be completely closed off to all construction traffic.”
Surface preparation for existing concrete slabs is “very different” than that for self-leveling cement to be stained or dyed, which is simply to “allow the self-leveler to dry/cure according to the manufacturer’s instructions, ensure the cured surface is clean, then apply stain or dye according to the product instructions and the specified design,” Cunningham stated.
Similar to pre-existing slabs, a self-leveling topping can also be engraved and textured to help hide cracks or bring out a different look. However, no matter what type of decorative surface is installed, the final appearance from using stains and dyes is hard to predict. For this reason, “a skilled and experienced decorative concrete contractor/artist is highly recommended. In most cases mockups and testing is conducted using all of the specified materials in an attempt to achieve a desired appearance/design. It is extremely important to set the expectations of the customer, and receive confirmation and acceptance of the mockups/samples prior to beginning work,” he said.
Coatings for Industry. Kevin Klotz, president, said his company offers decorative floor coatings including flake, quartz and clear sealers for stains and dyes. “Our recommended preparation procedure for a pre-existing slab would be to clean and degrease the slab through use of detergents, pressure washing and solvent cleaning as necessary, followed by diamond grinding to open the slab in order to accept a product – be it a sealer, stain, dye or other decorative finish.”
When choosing a self-leveling cementitious topping, “we recommend a diamond grind for the same reasons,” he added. “If using a self-leveling epoxy as a base for a decorative flake, quartz or metallic finish, the slab can also be prepared via shot blasting; this can only be used when a high-build coating is being applied.”
Installers and contractors have several options for hiding small imperfections in the substrate, Klotz noted. “Flake, quartz and metallic finishes all have the ability to hide different flaws in a concrete slab. It is also possible for the installer to create imitation grout lines throughout the floor to cover cracks and provide a more appealing finish.”
When a slab doesn’t stain in the intended way, “a metallic finish, such as Wearcoat Effect ME, can be used. It is a pigmented finish that has similar appearance and variability to a stain, but does not rely on the slab for the appearance and is inherently repeatable. With the ME, a solid color primer is applied, hiding many of the slabs discolorations or imperfections, and then a clear [coat] containing the metallic pigment is applied as a finish.”
The best conditions for installing his company’s products are “typically between 55 to 90 degrees Fahrenheit and no higher than 75% RH. When outside of these ranges, the drying or curing of sealers and coatings can be adversely affected, causing either too slow or too fast a cure and defects in the cured film, such as blisters or a change in gloss or color.”