When dealing with moisture problems, the best practice is measuring moisture content and relative humidity. The Ligno-VersaTec is one meter, which can measure relative humidity and moisture. For correlation between humidity and moisture see EMC-Chart.
The Ligno-VersaTec by itself is a pinless, dual-depth meter calibrated for wood, bamboo, drywall and many other materials. For measuring relative humidity the RH ThermoHygro probe can be added to any package listed below. Electrodes E14-V and E12 can be added for pin measurements.
Packages for monitoring come with Ligno-VersaTec meter, cables, screws and adapter H . Assortment of probes, pins and screws can be added to fit special applications. Cables can be ordered up to a length of 50ft.
Consider datalogger MC/RH Tracker to record ambient conditions and moisture in solid materials.