Concrete cellular structures are used extensively for residential buildings. In concept they are structurally simple but they require attention to detail to realise the benefi ts of ease of construction and economy. This guide is written for the structural engineer who has knowledge of building structures in general but who has limited or no experience of designing concrete cellular structures. It highlights areas that require close coordination between the structural and services engineers, the architect and importantly the system supplier. It also provides guidance on selecting an appropriate solution, sizing the structure and carrying out detailed design. Detailing considerations are explained, some of which have to be considered at the early stages of a project to achieve an effi cient building configuration.