Wood is a complex hygroscopic material with different mechanical properties that derive from its internal structure. Therefore, the material is influenced the most by relative humidity and temperature due to the properties of absorbing water if the environment is saturated or of desorbing it when the climate conditions change. The amount of water in the element is measured by the moisture content that is a critical factor in affecting the durability, performance and resistance capacity of wood. The changes that appear in the wooden element that are in compliance with the surrounding environment are followed by deterioration and loss of mechanical properties, eventually intervening in the safety of the building. Design models of timber structures take into consideration the moisture characteristics and its effects on engineered timber structural materials in order to create durable buildings. The main material used for the current analysis and experimental campaign is glued laminated timber, a sustainable structural product that has augmented properties, resistance and other advantages that support its use in buildings in the framework of climate change, sustainability and European policies. In the current study, the impact of relative humidity and temperature variations on the adhesive between glued laminated timber elements (glulam) and melamine urea formaldehyde (MUF) was analysed. The scope is to see how the adhesive-wood bond surface is influenced by the changes in moisture content in the wooden material and how it affects the resistance capacity of the whole element when shear force is applied. To observe the changes in physical and mechanical properties, relevant experimental research has been conducted.