When investigating moisture in building materials it is important to study both the actual and hygroscopic moisture contents (AMC; HMC) as well as the salt content. The presence of hygroscopic salts can often lead to misinterpretation of the moisture content and source. A high HMC can often be held responsible for a high AMC and result in an incorrect diagnosis and non-adapted treatment. We present a multi technique approach to investigate the presence of moisture and salts in the interior of a chapel in Imde-Meise, Belgium to provide advice for the optimal conservation.