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CONCRETE CONCERNS The realities of luxury vinyl installation By Lee Senter

The 2023 sales numbers for flooring are in and the results are indisputable. Luxury vinyl products account for a huge share of the flooring market and there seems to be no end in sight to growth in sales. More than 30 per cent of all sales, including ancillary items, were types of vinyl plank, reports retail and wholesale floor covering group CCA Global Partners. This year, the numbers are projected to reach 50 per cent. There are many categories of luxury vinyl flooring — plank, tile, rigid board, SPC, WPC, PVC-free and now new polyester planks. These products come in a variety of colours, patterns, locking mechanisms and construction methods. Today, as in years past, most floor covering purchase decisions are based on style and colour. Luxury vinyl products deliver on both. They also offer ease-of-maintenance to people with children and pets as these floors are simple to keep clean. But this is where the advantages end. Luxury vinyl products are often sold as waterproof, which leads potential buyers to believe they can be installed in wet environments. This is not necessarily true and many in the flooring and remodelling industries express concern about potential mould issues in the future. When flooring is installed on slab, on-grade or below-grade, it is not a question of if there is moisture in the concrete; rather, it is how much moisture is in the concrete. Up until 2000, most people put carpet in the basement. It makes sense because basement concrete slabs are rarely flat and level, and carpet allows moisture from the concrete to breathe through. Then more homeowners started to lay laminate wood flooring in the basement, which invariably fails and buckles if there is too much moisture in the slab. This, in turn, enables the substrate of the floor to breathe. Nowadays, the flooring of choice is luxury vinyl, but these products do not breathe and allow the moisture from the slab to escape. Worst yet, often the basement substrate underneath the vinyl is levelled with gypsum-based patching and other products that support mould growth. Wood subfloors and screeds also support mould growth, as do levelling compounds and household soils that remain on the substrate at the time of installation. The National Wood Flooring Association (NWFA) provides guidelines for moisture testing of wood and concrete substrates. For wood substrates, it is recommended to test for moisture at several locations in the room — a minimum of 20 per 1,000 square feet, paying special attention to exterior and plumbing walls — and average the results. A high reading in one area indicates a problem that must be corrected. For concrete substrates, NWFA accepts moisture testing to several ASTM standards (F2170, F1869, D4944, D4263 and F2659 for electrical moisture meters). Most installers in Canada use ASTM F2170, Standard Test Method for Determining Relative Humidity in Concrete Floor Slabs Using in Situ Probes, or ASTM F2659, Standard Guide for Preliminary Evaluation of Comparative Moisture Condition of Concrete, Gypsum Cement and Other Floor Slabs and Screeds Using a Non-Destructive Electronic Moisture Meter; that is, if they test the substrate at all. The only applicable standard for vinyl floor installation over a concrete slab is ASTM F710, Standard Practice for Preparing Concrete Floors to Receive Resilient Flooring. Most hardwood floor manufacturers follow NWFA guidelines. This includes recommendations that relative humidity in ambient air be 30 to 50 per cent. Many engineered wood flooring products have even higher relative humidity stipulations, as well as temperature range requirements. Vinyl, on the other hand, does not have a relative humidity requirement for ambient air; however, it has a temperature requirement, which includes limiting direct contact with areas of flooring that may be subject to excessive heat from sunlight through windows. Where the problem lies is most flooring installers do not have the necessary equipment to measure and/or monitor temperature and relative humidity. This includes a thermo-hygrometer for ambient air readings, which is also used to measure the relative humidity of the slab when following ASTM F2170 — the most commonly specified moisture test for concrete by flooring manufacturers. When it comes to non-penetrating moisture meters, few installers take requisite moisture readings of the wood and wood substrate prior to installation. What’s more, the meter most generally used does not read concrete moisture to a moisture content scale. For years, concrete meters have not been employed when installing floors but with the surge in vinyl and its increased use in basements, it’s imperative to ensure the concrete is dry before flooring installation. Otherwise, there is great potential for mould claims. ASTM F710 covers the procedure for determining the acceptability of concrete floors for the installation of resilient flooring. It also includes suggestions for ensuring the constructed concrete floor is acceptable for such installations, but it does not cover tests for adequacy of the concrete floor to perform structural requirements. A permanent, effective moisture vapour retarder of the specified thickness and permeance is required under all on- or below-grade concrete floors. Concrete floors for resilient floorings should be permanently dry, clean, smooth, structurally sound and free of substances that may prevent adhesive bonding. Surface cracks, grooves, depressions, control joints or non-moving joints and other irregularities should be filled or smoothed with latex patching or a recommended underlayment compound. The surface of the floor should be cleaned by scraping, brushing, vacuuming or any other method. All concrete slabs should be tested for moisture regardless of age or grade level, while all concrete floors should be tested for pH before installing resilient flooring. PREPARING THE CONCRETE FLOOR INSTALLATION MATTERS Lee Senter is president of the Canadian Flooring, Cleaning and Restoration Association (CFCRA). The CFCRA offers discounted moisture meters for members and installers to make doing the right thing easier and less expensive. It also provides online and in-person training at little to no cost to help flooring dealers, installers and restoration companies properly take moisture and temperature/humidity reading

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