Determining Moisture Content of Laminated Veneer Lumber (LVL)

Abstract

Wooden load-bearing structures are becoming more common as an eco-friendly alternative to steel and concrete in large buildings. In these buildings, laminated veneer lumber (LVL) is increasingly used in structural building elements, particularly in the flanges of wooden I-beams. However, as for all products made from wood, proper moisture control is important to ensure the long-term integrity of the elements. The purpose of this study is to investigate the moisture properties of LVL and the correlation between moisture sensor readings and the actual moisture content determined from accurate weighing of the samples. Laboratory measurements were made of two different wooden materials using 20 identical sensors. The test was conducted on samples of LVL flanges delivered by the Norwegian wood production company Hunton, and on samples of pine lumber. The moisture sensors were delivered by Omnisense. For the LVL samples, the test results show that the resistance values given by the resistance method were too high compared to the more accurate gravimetric method. Conversely, the measured values were too low for the pine samples. LVL also had a faster moisture sorption than pine under the same moisture conditions. The glue between the veneer layers affects the electric conductivity of the wood in LVL and interrupts the readings. The glue might also affect the moisture sorption.