Air gaps in building construction avoiding dampness and mould

Abstract

PurposeWater damage is a severe problem in modern construction, causing economic loss and health implications. The patented Air Gap Method, which is a slight modification of the common infill wall construction, provides means to build houses in a more robust way, minimizing the negative effects of water damage. This full‐scale study of the method aims to show how walls and floors may be built to create ventilation within the construction, with air gaps equipped with heating cables. The general hypothesis is that the patented Air Gap Method drains and evaporates dampness after water damage. The purpose of this study is to show how the method is built and how the method deals with water damage, such as a flooding, and with mould growth.Design/methodology/approachThe Air Gap Method is based on a common timber‐framed construction and is completed by the provision of inlets, air gaps, slits, and outlets. The power for the convective airflow is given by an electrical heating cable. The study was carried out as a full‐scale experiment using a 24 m2 large apartment build by this method. This apartment was flooded with 120 litres of domestic wastewater and the drying period was compared when heating cables were switched on or not. Mould growth was also investigated.FindingsThe method dries out a flooded floor in nine days when two heating cables were switched on, in 13 days with one heating cable and 21 days when the heating cables were off. The method prevents all mould growth provided that the indoor RH is lower than 65 per cent.Practical implicationsThe method provides means to build houses in a more robust way, minimizing the negative effects of water damage.Originality/valueThe issue of ventilated construction is rarely investigated in scientific research.