K-span system double corrugated trapezoid sheet profiles are used in construction engineering as self-supporting arch roofs for buildings. Some cases of failures of such structures have been reported. Deep, transverse corrugations in the profile surface, formed as a result of manufacturing, make the use of standard designing methods difficult. The paper presents a scientific approach to determining the load-carrying envelope of double corrugated profiles under complex load. Tests are carried out on small fragments of individual profiles under simulated load and support conditions. The results of the tests indicate the significant influence of transverse notches on the formation of local instability, which results in a change of their geometric characteristics and profile load-carrying capacity.