How does the calculator compute sag over time? (The Physics Behind It)

Wood and board materials have an important characteristic – they can continue to sag over time under constant load. This phenomenon is known as creep. Therefore, the calculator doesn't just compute immediate sag, but also uses an indicative model of long-term deformation based on common structural principles and approaches used in timber structure design (e.g., Eurocode 5).

While solid wood typically changes less, for particleboard, MDF, and other board materials, the sag after several years can be significantly higher than at installation—sometimes even multiplying. The calculation in this tool thus provides an indicative technical estimate of the material's behavior after 5 and 10 years in a standard dry interior. The results serve as a great guide for better visualization and safer furniture design, but they do not replace a professional structural engineering assessment.