Degradation of wooden products used in non-ventilated flat roofs

Abstract

In the recent years, the amount of flat roofs with load bearing structure from wood in Slovakia increases. This is caused by the costs and the effort to maximize the speed of built. Using the wood rafter in the flat roofs cause problem of using an organic material between two vapor tight layers, from interior a vapor barrier and from outside the roofing membrane. Additional, also oriented strand boards are also used instead of wooden boards. These are used either in condensations zones of the roofs or direct under the roofing membrane. This creates degradation of the material because of use in the humid environment in very short time. This paper briefly describes the state-of-art situation in Slovakia with some examples from the buildings and the numerical evaluation of the problem.