Investigation of water ingress to concrete basements

Abstract

In design terms, basements are water-excluding structures and there is a wealth of information available to aid the designer. Despite the comprehensive guidance available, there are still numerous instances of water ingress to concrete basements. One guide suggests that half of all basements leak at some time during their construction and that a significant proportion leak post-construction. By examining a number of case studies, the aim of this paper is to illustrate the reasons for such water ingress and possibly suggest how it can be avoided in the future. The case studies are divided into three topics – workmanship, unexpected events and cracking. There are many reasons why water ingress to concrete basements occurs, including poor workmanship and changing groundwater conditions. Most importantly, it needs to be accepted that reinforced concrete can, and in most cases will, crack and that water can make its way through these cracks. Water-resisting admixtures can prevent water seeping through the concrete material but not from passing through cracks that form in concrete.