A Damp Proof Course (DPC) is a physical barrier installed to the walls of a property as it is built.
The inclusion of a physical DPC was first introduced in 1875 though earlier methods have been identified.
Early workmanship was often poor and this can give rise to issues in dated properties.
How Can a Damp Proof Course Cause Damp?
Damp is a perennial issue in UK properties, and one of its lesser-known causes is a bridged damp-proof course.
Typically, it is accepted that a DPC protects your property from the ingress of rising dampness. However, it also prevents the ingress of rainwater splashback and other lesser-known methods of moisture ingress.
A bridged DPC occurs when the incumbent DPC becomes covered by obstructions such as soil, debris, or even structural alterations. When this barrier is blocked or bypassed, moisture can ascend freely through capillary action, causing dampness internally.
Often misdiagnosed as rising damp, the issue of lateral moisture ingress is a relatively simple fix once the culprit is identified.
What are the Sources of Briding?
Common sources of bridging include raised garden beds against external walls, poorly installed external cladding, raised paving to gardens and patios, infilling of areas adjacent to bay windows, or extensions that disrupt the continuity of the DPC.
Once breached, dampness can manifest in the form of unsightly staining, peeling paint, and even structural damage if left unaddressed. We often encounter issues with timber floor joists in properties that have a bridged DPC.
How Do You Combat a Bridged DPC?
To combat bridged DPC and the ensuing damp, it’s essential to maintain clear pathways for water to escape, and in severe cases, repair or replace the damp-proof course.
Regular inspections and addressing bridging issues promptly can help safeguard the integrity of UK properties against the ingress of moisture. Failure to inspect can cause your house to fall into disrepair.
We would also recommend that you consider the integration of surface water drainage.