When it comes to keeping your home structurally sound and free from moisture-related issues, there’s one problem you need to keep a close eye on. It’s called bridging, and it’s where moisture bypasses your damp-proof course (DPC) and can cause significant damage.
To know what to look out for and how to fix it, it’s important to understand what bridging is and how it occurs. We’ll explore all of this and more here.
What Is Bridging?
Bridging is the name used to describe what happens when moisture rises above the damp-proof course (DPC) installed in a building’s walls. This barrier is designed to stop ground moisture from rising upwards through the walls. The DPC is usually installed about 150mm above ground level.
However, if the damp-proof course is compromised or “bridged,” moisture can rise above it and enter the structure of the building. This leads to rising damp.
So, what causes bridging, and why do DPCs fail in this way? Here are a few of the main causes of the problem:
- High external ground levels – if soil or paving is piled up against an exterior wall above the DPC, it can create a route for moisture to bypass the barrier.
- Internal debris – rubble inside wall cavities or under suspended floors can sometimes act as a moisture bridge.
- Incorrect plastering – applying plaster that overlaps the DPC can allow moisture to transfer from walls to interior surfaces.
- Insulation materials – in cavity wall insulation in particular, poorly installed materials can cause or aid bridging.
The Impact of Bridging On Your Home
While a bit of damp might seem like a minor nuisance, the long-term implications of bridging can be far more serious. Persistent dampness can weaken masonry, corrode internal metal supports, and damage timber elements such as joists and floorboards.
Over time, this could potentially compromise the structural integrity of your property.
There’s another issue to consider, one that could affect your family’s health. Damp environments provide ideal conditions for mould and fungal growth, which can affect indoor air quality and lead to health issues such as respiratory problems.
Untreated bridging can also devalue your property. When selling a home, surveyors look closely for signs of damp and moisture ingress, and evidence of bridging can raise red flags for potential buyers.
Lastly, there’s the cosmetic impact of damp on your interior walls. It tends to spoil paintwork and plaster, and is not easily covered (it usually just comes back).
The Role of a Damp Expert in Fixing Bridging Problems
Identifying and fixing bridging isn’t always straightforward, often because it can be difficult to pinpoint the exact causes of damp.
This is where you might need to bring in a qualified damp expert. These professionals have the tools, training, and experience to:
- Diagnose the specific cause of moisture ingress
- Identify whether the damp is due to bridging, condensation, or another issue
- Recommend and implement effective solutions tailored to the type and severity of the problem.
There are a few solutions available, depending on your damp expert’s diagnosis of the problem. You may need to lower external ground levels, remove cavity wall debris, or have insulation professionally inspected. The DPC may be in need of repair or replacement.
You should also get advice on preventative measures to ensure the problem doesn’t come back.
When to Act
Homeowners should act at the first signs of damp, such as peeling paint, discoloured plaster, musty odours, or cold spots on walls. Even if the symptoms seem minor, they can be early warnings of a bridging issue. The sooner the problem is diagnosed, the less invasive and costly the solution is likely to be.
Addressing bridging issues early with a qualified damp expert can help avoid future structural concerns. Early intervention not only protects the integrity of the building but also preserves its aesthetic and financial value.
