We are engaged in some extensive below-grade alterations to an existing structure. The boundary wall of the existing basement is structurally sound but on one side is subject at various times to severe seepage. It is not possible to excavate to reach this wall or drain it on the outside. Are there any really effective measures that can be taken to correct the condition from the inside?
Yes. However, moisture may still persist in the wall even though the drain is installed and the waterproofing applied. Therefore every attempt should be made to find the source of the water seeping in. Proper grading, the laying of aprons or the digging of drainage ditches at appropriate locations could do much to cut off the trouble at the source. If the seepage is exceptionally severe it may be advisable to use a bituminous or a membrane waterproofing instead of the sand/cement mortar.