Date Published

17 August 2022

Document Type




Both the elastic deflection of loaded timber members and the relative movement of timber members mechanically fastened together increase with time. This time-dependent increase in deformation is termed creep.

Timber is particularly sensitive to load duration and creep effects, making it important to assess the creep deformations in any deformation calculation.

To calculate creep, all variable actions are first converted to an equivalent permanent action using the guidance given in Eurocode 0. The deformation produced by the resulting permanent action is then multiplied by a creep factor, kdef, to calculate the creep deformation. This document outlines the method involved.

Key Information

This sheet outlines a sample calculation of how creep could be calculated to express long term deflections for a timber beam as required by Eurocode 5.