For external walls the DPC should be applied 150mm a fresh bed of mortar, completely free of projections that may puncture the material or impede the material from lying flat. When joining two pieces of DPC they should be lapped over each other by at least 100mm.
For internal walls, DPC should be installed at the base of load bearing walls and linked with any adjoining DPM. The DPC should be at least the width the partition it is applied to and lapped by at least 100mm when two DPC's are joined.
