Many construction pathologies do not occur during execution, but after handover, once the building enters service. One of the frequent yet insufficiently discussed causes is incompatibility between materials, initially masked by an apparently correct appearance.

Incompatibilities may be chemical, physical, or mechanical. Chemical reactions occur, for example, between certain types of cement and reactive aggregates, between alkaline mortars and sensitive finishes, or between layers with different pH levels. The effects develop slowly: efflorescence, loss of adhesion, delamination, or accelerated degradation.

Differential thermal expansion is another major source of problems. Materials with different expansion coefficients—concrete, metal, ceramics, polymers—respond differently to temperature variations. Without properly sized joints and movement-accommodation details, cracking, detachment, and visible deformations may appear months or years after completion.

Degradation is further accelerated by water and vapor. Systems that appear airtight but contain layers incompatible in terms of vapor diffusion can trap moisture in sensitive zones. The result is reinforcement corrosion, mold development, or loss of thermal insulation performance.

The issue is not the lack of high-performance materials, but the lack of a systemic approach. Materials do not function individually, but as an integrated assembly. Without compatibility checks between layers, proper detailing, and adherence to system-based solutions, errors remain invisible—until they become costly.

(Photo: Freepik)