Patches, Skimcoats, and SLUs: Products and Technology Update
Manufacturers are hard at work introducing new technologies to their patches, skimcoats and self-leveling underlayments (SLUs) to make them compatible with today’s flooring requirements and ever-increasing, fast-track schedules. We spoke with industry experts in the segment to find out more about some of these technologies, and what products feature them.
Eric Carr, Custom Building Products senior director of commercial channel and product management: “Across the industry, the most important advancement has been the stability of the SLUs. They are much more crack-resistant than before due to the enhanced ability to flow over the surface as well as expand and contract. Another development is versatile primers that can be applied over porous as well as non-porous substrates including epoxy, such as our TechPrime A—an advanced acrylic multi-surface primer. Both technologies deliver better performance to the flooring contractor and ultimately the project the owner.
“CustomTech Flooring Preparation Systems, co-developed by Custom Building Products and top commercial contractors, has introduced several new products to its lineup. TechLevel WSF is a fiber-reinforced SLU for wood subfloors. No lath is required over plywood or OSB, it can be used in place of backerboard down to 1/4 in. and the product is compatible with most radiant heat systems. TechLevel WSF is an excellent product for above-grade concrete substrates due to the higher polymer loading and intermeshing fibers that give it extra flexural strength.
“Coming in with higher compressive strength is our TechLevel 150 calcium aluminate-based SLU, another high-flow formula with excellent handling and exceptional flow retention. Like WSF, TechLevel 150 features Low Prep Technology, so no mechanical prep is required for suitable substrates.
“For patching from featheredge up to 1 in., CustomTech offers Silk, a rapid-curing finishing compound that provides an ultra-smooth finish and allows installation of floor coverings in as little as 30 minutes. Silk is very easy to work with and very forgiving for the installer.”
Annika Oeing, Ardex Americas marketing communications manager: “Most of the latest technologies we are seeing are focused on the ability to handle moisture, as well as more universal products that work on a wider varieties of substrates. As manufacturers, we are constantly challenged to make sure we have a solution that can handle any jobsite circumstances.
“Ardex K 60 Arditex is a rapid-setting latex SLU. It is mixed only with a latex additive, and addresses both of the situations we discussed concerning moisture resistance and its universal characteristics. It can be installed over a wide variety of substrates without the use of a primer, including permanently wet areas, and can be installed over the Ardex MC Rapid moisture control system.
“We also offer a new skimcoat and patch product, Ardex MRF. It’s an unsanded underlayment that can be used in applications that are exposed to moisture indefinitely, such as exterior use and under moisture control systems. It features the unique Ardex Weatherproof Technology.”
Brian Pistulka, MAPEI business manager for tile and stone installation systems: “Today’s trend of Large and Heavy Tile (LHT) or Gauged Porcelain Tile installations coupled with modern fast-paced construction practices have resulted in the need for polymer-modified and fast-setting prep products. The finished walls and floors being provided to the tile contractor often need leveling or patching to provide a flat surface to receive large-format tile, which spurred the development of new product solutions with higher-performance properties.
“Fast-setting prep products are looked to as the solution to shorten normal curing time requirements, allowing the contractor to render, slope, patch or level the substrate as needed for today’s tile, while reducing downtime before tile installation. Planitop 330 Fast (a quick-setting, polymer-modified, fiber-reinforced cementitious rendering, patching and leveling mortar) and Planislope RS (a rapid-setting, pre-blended, polymer-modified sloping mortar) are MAPEI’s latest products for fast-setting solutions.”
Jeff Johnson, MAPEI business manager for floor covering installation systems and surface preparation products: “The latest technology to hit patches and skim coats is high moisture tolerance. Traditional polymer-modified patching or skim-coating compounds do not perform well at high moisture levels. In worst-case scenarios they will soften, delaminate and cause a floor installation to fail. Traditional SLUs are also sensitive to high moisture conditions, where the excess moisture can cause them to expand, causing delamination and subsequent floor failure.
“Therefore, new products needed to be developed that are unaffected (or even get stronger) in high moisture conditions. The trick to the development of these products was not only to make them moisture resistant but still be familiar in terms of handling characteristics for the installer.
“Our latest technologies can be found in MAPEI’s Planiprep MRS (a moisture-resistant, high-compressive strength skimcoating compound), Mapecem Quickpatch (a high-performance concrete patch) and ULTRAPLAN Extreme 2 (a weather-resistant, high-compressive strength SLU).”
Michelle Eubanks, Schönox HPS North America senior marketing and communications manager: “We’re seeing a new generation of hybrid self-leveling systems on the market. Hybrid systems like Schönox AP Rapid and AP Rapid Plus combine the versatility and strength of synthetic gypsum with the speed of fast-curing cements.”
Kevin Pollard, USG marketing communications manager: “Patch and repair products that exhibit high moisture and pH tolerances are becoming a necessity when preparing concrete for today’s high-performance flooring systems. USG Durock EXG Concrete Repair Patch is a high-performance, air-entrained cementitious patch suitable for wet interior and exterior applications, and is an ideal solution for use under high RH-tolerant floor covering adhesives and systems. It reaches up to 10,500 psi, making it a viable patch solution for garages and driveway repairs. Due to its special chemical composition, the patch develops excellent bond to concrete substrates without requiring a bonding primer and allows for the application of floor coverings in as little as 45 minutes and vehicle traffic in as little as one hour.
“For many other patching products and SLUs, preparing the concrete substrate first is an extremely important step. USG Durock LSP Liquid Surface Profiler features a proprietary chemistry that is biodegradable, self-neutralizing and low VOC. As USG Durock LSP reacts with and breaks down the free minerals and contaminants residing in the top 3 to 4 mm of the concrete surface, impurities are lifted to the surface for easy removal. Concrete surface profiles (CSP) of 1 to 3 can be easily achieved after just one application. For heavily soiled concrete, or when a CSP of 3 to 4 is required, two applications may be necessary.”
Alan Kin, Texrite technical sales manager: “Surface preparation for vinyl, wood and ceramic finished flooring is seeing a rise in the need for patches, skimcoats and SLUs. The larger, longer formats of these finished floors immediately show any surface imperfection in the slab or substrate. This in not to imply the substrates are not within construction standards; however, there is a consumer aesthetic demand for a mirror-flat surface that can only be achieved with patches, skimcoats and SLUs.
“Advances in technology for this group of products has given more choices to the professional installer. The newer patches, skimcoats and SLUs are easier to mix, trowel and apply. They also typically allow multi-surface bonding and rapidly reduced cure time.
“Texrite offers Featherite 125 fs skimcoat and patch, which can be applied skimcoat-thin to 1/2 in. thickness and then be sanded or walked on in 60 to 90 minutes. It is able to bond to both concrete and exterior glue plywood (EGP) surfaces.
“For the installer needing maximum interior floor leveling in the shortest amount of time, Texrite Flowrite 250 fs is a rapid-curing self-leveler. It offers 15 minutes of flow time and allows surface walk ons time in 2 to 4 hours. The enhanced formula features a higher content of aluminate cement, which allows for faster dry and cure times.”