Directional characterisation of annual and temporary exposure to rainwater penetration on building façades throughout Mexico

Abstract

Rainwater penetration on building façades has a significant impact on the durability, hygrothermal performance, and habitability of buildings. This research characterises the directional exposure of Mexican façades to rainwater penetration by identifying wind-driven rain (WDR) and driving rain wind pressure (DRWP) throughout the country. For this purpose, climatic datasets of daily resolution gathered at 527 weather stations between 2003 and 2018 were analysed. As a result, isopleth maps of annual scalar values of WDR, DRWP, and the approximate orientation of their directional maxima were produced. The joint risk of rainwater penetration (defined by both factors) and the applicability of novel extrapolation that estimates the maximum directional exposures anywhere in Mexico from scalar results are also discussed. Additionally, the influence of certain tropical cyclones on the exposure was characterised, leading to the identification of preliminary patterns associated with these temporary WDR and DRWP exposures. Such extreme climatic events can cause, in a short interval of time, as much WDR as that occurring during the rest of the year and DRWP that is 2–5 times higher than the mean annual value. In general, the highest level of hazard of rainwater penetration on façades was identified west of the Isthmus of Tehuantepec and on the coast of the state of Veracruz.