Indoors and out, decorative concrete overlays permanently cover up surface imperfections in existing concrete, giving them any new look imaginable at a much lower cost than removal and replacement.
Today’s cement-based overlays combine polymer resins with cement, sand, acrylics or acrylic blends and other additives to improve performance, wear resistance, beauty and shine. They adhere well to existing concrete and resist damage from salt, chemicals, UV exposure, freeze-thaw conditions and abrasion.
The most popular types of decorative concrete overlays include stamped and stained concrete, and the popularity of other types varies in different areas of the country:
- Exterior knock-down finishes are popular in the Sunbelt regions
- Hard-troweled interior microtoppings are popular in metropolitan regions
With many options available, you’re sure to find at least one system that offers the most variety in color and finish while meeting your requirements for durability, appearance, maintenance and cost. Contractors must pay critical attention to adequate surface preparation, the most critical factor to long-term performance. For this reason, they prefer mechanical surface preparation, which does a more thorough job with the same grinding equipment and diamond tooling used for polishing concrete.
How to Concrete for Decorative Overlays in Extreme Weather Conditions
Concrete experts like the Portland Cement Association suggest contractors employ hot weather concreting procedures if the ambient temperature is forecast to exceed 77°F. Hot weather, high wind velocity and low relative humidity force higher concrete temperatures, which in turn increase the water-cementitious materials ratio, resulting in lower strength and reduced durability. Concrete will not only set quicker; the high rate of evaporation can cause early-age shrinkage and cracking before concrete sets. Thermal cracking can occur from rapid temperature changes such as those from a hot day to a cool night.
4 Key Temperatures to Check
- Air or Ambient Temperature
- Concrete Substrate Temperature
- Materials Temperature
- Water Temperature
Knowing these temperatures and employing the installation guidelines described below will help ensure the desired results are achieved.
10 Installation Guidelines for Hot Weather Concreting
- Store materials in a cool, dry place, rather than on-site underneath a tarp, which can get very warm.
- Plan the installation early in the day, when both air and substrate temperatures will be at their lowest.
- Substrate temperature is most important. Use a surface thermometer to determine the deployment of hot weather concreting procedures. Tenting or shading the installation area can help control substrate temperature.
- Work the materials more quickly and in smaller areas. It is critical to use the right tools, including heavy-duty drills for mixing, to maximize efficiency. Providing sufficient labor will minimize the amount of time required to place and finish the materials.
- Make modifications to concrete mixtures. Adding retarders, water reducers, extended set-control admixtures, slag cement or synthetic fibers can reduce slump loss, setting time and plastic shrinkage cracking.
- For exterior applications, erect temporary wind breaks to prevent rapid evaporation due to air movement over the surface. Use sunscreens, mist fogging or evaporation retardants.
- Chill mix water and store aggregate in a cool, dry place. Blocks or bags of ice in a 55-gallon drum of water will chill the water to increase working time. In the case of a pump installation of a self-leveling material, sections of copper tubing or coiled garden hose packed in a drum of ice will chill the water on its way to the pump, also allowing for a longer working time.
- The mixing bucket or barrel must be cleaned before mixing a fresh batch of material. Leftover material on the sides of the mixing bucket or barrel can accelerate the set times of the materials.
- Consider using accelerators to expedite finishing operations and avoid plastic shrinkage cracking.
- Where possible, halt concrete work until the temperature is more conducive to a successful installation.
Runyon Surface Prep is a full-service stocking distributor for all your concrete prep, polishing, decorative, repair, restoration and maintenance needs. We carry the following:
CTS RAPID SET 50 POUND TRU SELF-LEVELING CEMENT – Use CTS Rapid Set TRU Floor Self-Leveling Cement for high performance floor topping, underlayment and resurfacing projects. TRU Self-Leveling is ideal for projects that require long life and working time. It settles to a light off-white color ideal for stained, dyed or decorative aggregate flooring. Not only can TRU grind, but it can also be used to polish, making it ideal for those shiny decorative floors.
CTS RAPID SET 50 POUND TRU GRAY SELF-LEVELING – Use Rapid Set TRU Gray Self-Leveling when you need a high quality, fast, cement gray topping that can be polished. TRU Gray is a high performance, architectural topping and resurfacer that can be used indoors and outdoors, in wet or dry environments. It is ideal for projects that need long flow life and working time while achieving high early strength. A customized appearance can be achieved by adding decorative aggregate.
CTS RAPID SET 60 POUND TRU PC POLISHED CONCRETE TOPPING – Use Rapid Set TRU PC Polished Concrete Topping when you need your floor ready for foot traffic in 2 to 3 hours. It is a professional grade, hydraulic cement-based, self-leveling topping that can be ground and polished to expose the aggregate and simulate the appearance of polished concrete. TRU PC levels rapidly, maintains workability for up to 20 minutes, produces a dense surface, and has high bond strength. As an interior and exterior product, TRU PC is durable in wet or dry conditions.