In this paper the effect of durability modelling on the design of a textile reinforced concrete (TRC) building element is studied. The effect of long-term evolution of the strength is discussed for self-bearing sandwich elements with TRC faces, used as wall cladding elements. In this paper, focus is put on design according to ultimate limit state. Several strength loss models are calibrated on accelerated ageing experiments. These calibrated models are then used to make long term predictions for the sandwich panels and results are discussed. © 2006 Institute of Fundamental Technological Research, Warsaw. All rights reserved.