In construction, the difference between a profitable project and a problematic one is often measured in millimetres. Permissible tolerances—those deviations considered acceptable between the design and actual execution—are essential, yet frequently underestimated.

Projects are designed in ideal conditions, but construction sites operate in a very different reality: material variations, installation errors, weather conditions, and altered execution sequences. When tolerances are not clearly defined or properly understood by all parties, hidden costs inevitably arise.

A common example is the mismatch between the completed structure and finishing or façade elements. Seemingly minor deviations can lead to rework, improvised adjustments, or costly corrective solutions. In building services, poorly coordinated tolerances result in clashes between routes, incorrectly positioned openings, and additional execution time.

Paradoxically, tolerances that are too tight can be just as costly. They increase execution requirements, demand more highly skilled labour, and raise the risk of non-compliance. In the absence of solid technical justification, such tolerances become a source of losses.

Where is money actually saved? In coordination. Well-detailed projects, with tolerances adapted to the type of construction and materials used, reduce rework and on-site conflicts. Execution is not about perfection, but about intelligent control of deviations. Where tolerances are properly understood, costs remain under control.

(Photo: Freepik)