INTERIORS 75


MANAGE MOISTURE & AVOID FLOOR FAILURE


Excess subfl oor moisture causes fl oor failure and costly delays to projects. Stephen Boulton of F Ball & Co provides some crucial advice for developers to help them guard against the problem when installing fl oorcoverings.


Digital hygrometers are affi xed to the subfl oor at regular intervals to accurately measure subfl oor relative humidity (RH) levels


Application of a liquid waterproof surface membrane with a roller


A fast-track liquid waterproof surface membrane can be used to create a barrier against residual construction moisture where relative humidity levels are up to 95%


U


nchecked subfl oor moisture, whether residual construction moisture or rising damp, can attack


fl ooring adhesives and fl oorcoverings, causing wood to warp and damaging textile fl oorcoverings by promoting mould and bacterial growth. ot only can this ruin the fi nished appearance of a fl ooring installation, but it can potentially cause fl oorcoverings to debond, resulting in complete fl oor failure, and present a health haard. echnical service departments freuently receive enuiries from contractors who have been contacted to rectify a recent fl ooring installation where fl oorcoverings have begun to lift as a result of unmanaged excess subfl oor moisture. o prevent fl oor failure due to excess


subfl oor moisture, it is important to take time to determine subfl oor moisture levels and deploy an appropriate moisture


management solution, where necessary, prior to installing fl oorcoverings.


TESTING


It is recommended that a moisture test is undertaken as part of any fl ooring installation, having fi rst prepared the subfl oor so that it is suitably smooth, sound and free of contaminants. If the subfl oor elative umidity  levels exceed   if wood fl oorcoverings are to be installed, a moisture management solution will be reuired to prevent excess subfl oor moisture attacking adhesives and damaging fl oorcoverings. A uick, nonintrusive way to identify the presence of subfl oor moisture is to use a handheld radio freuency moisture meter. If the device indicates the presence of moisture in the subfl oor, further testing will be reuired to determine the precise subfl oor relative humidity levels and if a moisture management solution


is reuired. he only method of measuring


subfl oor relative humidity levels with certainty, and the method advocated by ritish tandards, is to use a calibrated hygrometer. hese devices measure the relative humidity of a small volume of confi ned air in euilibrium with the subfl oor, taking into account the ambient temperature. he device is affi xed to the subfl oor using butyl tape to create an airtight seal around the base of the instrument. It is then left for a suffi cient amount of time to allow trapped air to reach moisture euilibrium with the screed or base before the unit is switched on. uilibrium can generally be assumed after leaving the instrument overnight and readings taken four hours apart are identical. It is recommended that multiple digital hygrometers are placed at regular intervals across the entire subfl oor area


TO PREVENT FLOOR FAILURE DUE TO EXCESS SUBFLOOR MOISTURE, IT IS IMPORTANT TO TAKE TIME TO DETERMINE SUBFLOOR MOISTURE LEVELS AND DEPLOY AN APPROPRIATE MOISTURE MANAGEMENT SOLUTION


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