Creating a Sound Foundation
Stephen Boulton, Technical Service Manager at F. Ball and Co. Ltd., outlines some of the key factors to consider when specifying subfloor treatments.
helps to guarantee its long-term performance.
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Protecting against moisture
Excess moisture is one of the major causes of floor failures. If damp floors are left untreated, the floor covering will effectively act as a barrier, trapping moisture beneath it. The presence of excess moisture can impact dramatically on the appearance and performance of a floor in many cases causing blistering of the floor surface or even total failure of the flooring adhesive, causing the floor covering to lift or pull away around the edges.
The presence or absence of moisture at the surface of a subfloor can initially be checked using a handheld radio frequency meter. Quick and easy to use, these devices provide an instant reading that indicates whether moisture is being released or not, in conjunction with site information. If no moisture is present, then the flooring installation can proceed as planned. However, if the device indicates high levels of moisture, further tests must be carried out using a floor-mounted, pre-calibrated digital hygrometer.
areful consideration of the requirements for flooring preparation at the outset of a project helps to ensure the most appropriate complete flooring system is installed. This not only enhances the aesthetic appearance of the floor covering but also
Providing a more accurate measurement method, digital hygrometers are used to directly measure the Relative Humidity (RH) level of the subfloor. In accordance with BS 5325 and 8203 standards, where relative humidity levels are measured at below 75 %, the flooring installation can proceed without further moisture prevention treatment to the subfloor. However, at levels over 75 % RH, the application of a waterproof surface membrane is required. Moisture can be effectively suppressed using an epoxy resin
system. To aid coverage uniformity, a resin system should be selected which is pigmented, allowing the user to visually control product coverage. Alternatively, in listed buildings, buildings that are occupied on a limited tenancy, or where under-floor heating is present, an impervious loose lay sheet membrane can be applied. These systems provide a physical barrier to moisture, as well as allowing the easy removal of floor coverings at the end of the installation, leaving the subfloor in its original condition.
A smooth selection
A smoothing underlayment should then be installed to create a
smooth and level surface for the new floor covering. This will not only help to optimise the aesthetic appearance of the new floor but will also minimise premature wear areas. Applying diluted general- purpose neoprene primers over absorbent concrete subfloors helps to promote the adhesion of the smoothing underlayment.
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