Requirements for Foundations and Rising Walls
Foundations to be provided for all brick and block walls, chimneys and load bearing partitions including load bearing stud partitions. All internal foundations are to be the same thickness and depth as the external wall foundations.
Diagram B33 - Detail A - DPM installation where internal floor level is below ground floor level
In order to reduce the risk of clogging by migration of fines it is recommended to wrap the perforated drain in a geotextile filter.