The aging process is a natural occurrence for all materials. Building materials also age, and every building wears out over the years. Its technical condition constantly deteriorates with use. To maintain buildings in optimal condition, it is essential to address renovation challenges. The primary objective of the developed building deterioration forecast is to accurately predict the timing of potential damage, enabling optimal planning of renovation projects. This paper introduces a degradation model for an unrenovated building, focusing on aging hazards. The model adapts mathematical frameworks used to assess the reliability of mechanical and electronic equipment, contributing to the overall building life cycle analysis. The mathematical formulation of the degradation model is derived from an examination of the correlation between damage intensity, performance changes, and the ageing hazard stream function of building components. The analysis of the building degradation process utilizes an ageing model previously established by the author, wherein the function representing changes in performance characteristics over the building’s lifespan reflects its technical condition. A comprehensive understanding of the degradation process throughout the entire lifespan of a building will facilitate the assessment of remediation strategies. Predicting the aging process of a building is needed when making investment decisions, and there is a lack of developed forecasts of building degradation. The model of aging of a residential building presented in the article is a proposal for a view of the building as a technical object.