This report summarizes current best practice and provides guidance on the construction and improvements of water resisting basements. It assists architects, engineers, surveyors and their clients with decision making on the control of the basement's internal environment, and the means of construction and maintenance. It takes account of viable construction methods - for both deep and shallow basements - together with the active and passive precautions available to achieve the most appropriate and economic environmental control system. The topics covered include: internal and external environments; design of new basements; external drainage positions; water and vapour resistance of residential basements; refurbishment and upgrading techniques; rising groundwater; comparison of British design codes; example calculations for heating and ventilation; and materials.