The article analyzes the use of ash foam concrete filler structures based on ash from sludge combustion for high-rise construction. Physical and chemical as well as physical and mechanical studies of samples of structures made of ash foam concrete were carried out. Ash foam concrete was produced with the use of ash from sludge combustion instead of natural sand after long-term operation of building structures. The improvement of the material in thermal protection is shown. Phase changes in the structures over time which is more than 12 years are traced.