Hardwood Floors February/March 2019

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AT THE SITE Sweeping Not Always the Only Preparation Needed (Continued)

SCENARIO 2: A client has a commercial building that is very old. The concrete slab has been maintained well and has had other flooring material installed for years. The client now wants to install hardwood flooring and give his office a new look. Although modern building codes require vapor barriers to be placed under concrete slabs on grade, these can fail over time and were not required decades ago. Failure is caused by subbase material penetrating the barrier, roots, or damage during placement of the concrete. This can lead to unknown excessive moisture, especially if the original floor covering is breathable and did not show any signs of moisture issues. Proper acknowledgment of these concerns will aid in fewer issues at a later date.

of adhesive needs to be used with your wood flooring or if a moisture mitigation systemwill be needed prior to leveling the floor. Slab moisture testing should be conducted by a trained professional who is certified to perform the testing and accurately report reliable test results. The ICRI “Concrete Slab Moisture Testing Technician (CSMTT)” certification program trains and certifies individuals to properly perform slab moisture testing and report consistent, accurate, and reliable test results that will help the owner, specifier, and contractor make informed decisions as to when a concrete slab is ready for a floor covering installation. Some scenarios where surface preparation of the concrete substrate may be required are as follows: SCENARIO 1: During placement of a new construction, slab on grade, it started raining. Unprepared, the contractor finished the slab and left it alone. Previously in the article, it was stated that concrete has to be flat and dense to receive hardwood flooring. Typically, when excessive moisture, such as rain, occurs during the placement or finishing process of concrete, both flatness and density may be compromised.

SCENARIO 3: A concrete slab was placed with two or three concrete finishers working at the same time. Not knowing what the final flooring would be in areas of the building, the concrete was finished out of tolerance for a flat slab. The owners and designer will not change flooring options due to this mistake, and no one wants to tear out and replace the slab. Finishing errors can occur on concrete placements. Identifying these errors prior to installation of the flooring is the ideal scenario to remedy before the flooring is installed. A combination of methods and materials may be required due to intermittent finishing errors. These are only a few scenarios of how the ICRI’s guideline could be utilized on your next hardwood flooring installation. Within the guideline, recommendations for CSP range by the material to be installed as well as surface preparation methods that can achieve these profiles are provided (Fig. 2). The guide also touches on jobsite requirements that normally may be overlooked, including vibration, noise, environmental/safety factors, equipment details and limitations (no one wants to show up with a 48" [121.9 cm] wide shot blast machine only to find out the doorway opening is 32" [81.3 cm]), and more.

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