The paper presents the results of the study of the condition of wooden structures of the attic floor of the St. Petersburg Theological Academy of the Russian Orthodox Church. The main defects and damages of the rafter system elements are indicated. Conclusions are given on the physical and mechanical characteristics of a beam over 200 years old. Conclusions are made on measures to maintain the operability of the structures.

Keywords: load-bearing capacity of wooden structures, biodestructors, strength reduction, rafter system

The paper presents a study of the resistance of connections of load-bearing laminated wood structures using domestic melamine-urea-formaldehyde adhesives (MMFC) to cyclic temperature and humidity influences. The method of cyclic tests is described. An assessment is made of the resistance of MMFC to temperature and humidity influences and the compliance of the selected adhesive with the requirements established for the production of long-span load-bearing structures.

Keywords: melamine-urea-formaldehyde adhesives, wooden structures, resistance of adhesive joints to cyclic temperature and humidity influences, strength

The paper presents a study of the water resistance of joints of load-bearing laminated timber structures using domestic melamine-urea-formaldehyde adhesives (MMFC). The high relative strength of samples dried after soaking and boiling above that established for the increased water resistance group is shown. An assessment of water resistance for three formulations is given, the dynamics of crack growth due to the influence of the moisture factor of MMFC.

Keywords: melamine-urea-formaldehyde adhesives, wooden structures, water resistance of adhesive joints, strength