The features and results technical inspection structures of waste water treatment building of North-West TEC in St.-Petersburg are described. Non-load-bearing brick walls and reinforce–concrete columns lean on concrete foundation slab. The reasons of crack origin and development in brickwork are exposed. The main reason is uneven deformations of foundation slab at the different filling of reservoirs. The results of instrumental reserches and model experiment are confirmed by calculations. Offered and realised measures of constructions strengthening, after that cracks development was halted.