Bridging (DPC)
/BRIJ-ing/
Also known as: DPC bridging, bridged DPC, damp bridge
Definition
The term used when a material or build-up inadvertently creates a path that bypasses or bridges over a damp proof course (DPC), allowing moisture to travel from below the DPC level up into the building fabric. Common causes include soil or render built up against a wall above the DPC line.
In Practice
Bridging of the DPC is one of the most common causes of rising damp symptoms. Typical bridges include: external render taken below DPC, garden soil or paving raised above the DPC, internal plaster run down to floor level, and debris in a cavity. The remedy is to expose the DPC line and remove whatever is bridging it. Ground levels should be kept at least 150mm below the DPC.
UK Building Regulations
Approved Document C - Site Preparation
Approved Document C requires that external ground levels are kept sufficiently below the DPC to prevent bridging. A minimum 150mm clearance is standard practice.