Evaluation of Various Brands of Moisture Meters in Gypsum and Wood Substrates at a Range of Moisture Contents

Determining correct moisture content of wetted building materials and analysis of corresponding locations, orientations,and patterns is of imminent value to Forensic Engineers and building scientists. As many building damages relate toinsurance claims and construction defect/ subrogation lawsuits, legal challenges to the accuracy of measured moisturecontent have arisen. The objective of this study was to independently establish the level of precision of common moisturemeters used to quantify and measure moisture content in building components. The study tested four different brandmoisture meters in gypsum and wood substrates at normal, high, and saturated moisture contents. The results werecompared against laboratory obtained moisture content to assess the accuracy of each meter in the substrate and at whichmoisture content range.The study wetted wood and gypsum specimens to moderate and saturated conditions and measured the resulting moisturecontent with the four different brands of meters. Control wood and gypsum specimens were not exposed to water and theirmoisture content was measured as is. All of the wood and gypsum specimens were subsequently sent to a laboratory andmoisture content was calculated by the oven-dry method. The moisture content results measured by moisture meters werecompared against the laboratory obtained data. Data was averaged and plotted with moisture content of various specimensand visually analysed to determine which meters deviated from the laboratory data and at which moisture contents. Datawas also numerically analysed and graphed to quantify meter moisture content accuracy as compared to laboratory obtainedmoisture content.Moisture meters should be used within the manufacturer specified range of moisture content and price may not be the bestindicator of moisture meter accuracy. At low ranges of moisture content in wood and gypsum, all meters exhibitedrelatively small deviation from laboratory calculated values, while moderate and saturated conditions presented largervariations from laboratory moisture content. Composite materials such as gypsum may be difficult to establish moisturecontent, as different materials such as the gypsum core and paper facing absorb and distribute moisture differently. Allmeters were successful in detecting wet conditions, but exhibited a lack of precision in determining exact values inmoderate and saturated conditions. In this regard, meters may be improved as the industry demands not only detecting wetconditions but determining precise values at a full range of moisture contents. Future studies may be limited to monolithicmaterials as oven dry method returns an average value of the respective paper and gypsum components in gypsum boardspecimens, and thus contained an inherent margin of error.

کلیدواژه ها:

Forensic Engineering ، Building Science ، Material Science ، Moisture Meter ، Water Exposure ، Building Materials ، Duration ofLoss ، Wood ، Gypsum Board ، Drywall ، Sheetrock ، Roof Leak ، Plumbing Leak ، Insurance Claim