The best approach for any water-related issue is to determine the cause, which can vary depending on conditions, such as soils, drainage and maintenance of supporting systems. Once the source is determined, the type of repair can be established. Making sure not to compromise or interrupt the operation of existing systems within the living environment. Drainage still needs to occur in any system, blocking or just sealing the wall will build up hydro-static pressure on your foundation and eventually cause more damage.