Hygrothermal behavior analysis of construction systems applied to underground elements in high water tables

The moisture problems in buildings that present underground and semi-underground elements with high water table levels affect technical and economic decisions. This article shows several analysis of the mechanisms involved in moisture and heat transport, taking into account two different seasons, a rainy and a dry one, for the years of 2001 and 2002, in Brasília, Brazil, employing the WUFI 2D-3 program. Applying known data and program inputs, it was possible to present hygrothermal characteristics of the materials and variation of groundwater. The climate in Brasília, Brazil, was critical during the rainy season between January and March 2001, showing no significant differences between the dry seasons. There are significant changes in water content and relative humidity in the materials for water tables at 1,0 m deep, in soils as clay, sand and sand-clay, also presenting significant risk of fungal proliferation. The decision to implement a drainage system will depend on the water-level fluctuations in distinct periods of the year and on the soil type, hence the project designer shall dimension the drainage system considering lowering the water table at a minimum of 1,0 m in relation to the lowest elevation in buildings.