If you’re seeing damp rising higher than expected on your internal walls in Bolton — especially above skirting level — the issue may not be rising damp at all.
One of the most common causes we find is DPC bridging.
DPC bridging occurs when something allows moisture to bypass the original Damp Proof Course and reach the inner wall fabric. It can happen both internally and externally, and it’s often misdiagnosed.
At Weather Wise Solutions Limited, we help Bolton homeowners identify whether their wall is truly suffering from rising damp or if the DPC has simply become bridged.
🔍 What Is DPC Bridging?
The Damp Proof Course (DPC) is a barrier designed to stop moisture rising from the ground.
When something creates a continuous path between the ground and the internal wall above the DPC, water can bypass the barrier.
This is known as bridging, and it’s responsible for a large percentage of rising damp misdiagnoses in Bolton homes.
🧱 Common Causes of DPC Bridging
1️⃣ External Ground Levels Too High
If soil, tarmac, gravel or paving is higher than the DPC line, moisture can soak directly into the wall above the barrier.
Signs include:
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damp patches at the base of internal walls
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blistering plaster
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rotten skirtings
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efflorescent salts
This is one of the most common causes.
2️⃣ Bridging Within the Cavity
Cavity walls work by keeping the inner leaf dry.
If the cavity becomes bridged, moisture transfers straight across.
Typical causes:
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mortar snots
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rubble dropped during construction
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poorly installed insulation
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render falling into the cavity
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debris after window replacement
This can cause damp patches, crumbling plaster and persistent salt deposits.
3️⃣ Plaster Touching the Floor (Internal Bridging)
If the internal plaster sits tight to the floor, it can form a moisture bridge above the DPC.
Signs include:
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damp staining right above skirting level
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salts forming in a horizontal band
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skirting board decay
Weather Wise sees this frequently in Bolton homes where dot-and-dab or older plaster systems meet the floor.
4️⃣ Solid Floors Meeting Internal Walls
If a solid floor has been laid too high, it may bridge the DPC, allowing moisture to pass into the wall base.
5️⃣ Blocked or Altered Ventilation Paths
If airflow around the wall base or subfloor is poor, humidity remains high and moisture reaches the wall base more easily.
🧰 How Weather Wise Diagnose DPC Bridging in Bolton
Our trained damp specialists use a structured approach:
✔ Moisture Mapping
To identify moisture patterns and confirm whether damp rises from the base or is caused by bridging.
✔ External Level Check
Measuring ground levels in relation to the DPC line.
✔ Cavity Investigation
Using cameras or removing bricks where needed to inspect cavity bridges.
✔ Plaster Line Assessment
Checking whether the plaster or skirting meets the floor.
✔ Salt Testing
To determine whether the salts are consistent with ground moisture.
🛠️ How We Fix DPC Bridging (Internal & External)
🔨 External Solutions
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lowering ground levels
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installing drainage channels
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removing render below DPC
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clearing cavities
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repairing pointing or brickwork
🪚 Internal Solutions
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removing bridging plaster
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installing new salt-resistant plaster
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raising skirting height
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correcting floor-to-wall junctions
🌀 Ventilation Improvements
To stabilise humidity and prevent moisture accumulation.
We use quality materials from:
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PAM Ties: https://www.pamties.co.uk/
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Wycamol: https://wykamol.com/
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Builders Super Store
As members of:
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Federation of Damp – https://federationofdamp.co.uk/
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Damp Proofing Association – https://www.dampproofingassociation.co.uk/
we follow trusted industry methodologies.
Eligible works include insurance-backed guarantees.
🏡 Why Bolton Homeowners Trust Weather Wise
Weather Wise Solutions Limited is a family-run damp company serving Bolton and Greater Manchester.
We focus on accurate diagnosis, long-term repairs, and transparent advice.
We are trusted and verified on:
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TrustATrader:
https://www.trustatrader.com/traders/weather-wise-solutions-limited-damp-surveyor-newcastle-under-lyme -
Checkatrade:
https://www.checkatrade.com/trades/weatherwisesolutionslimited
📞 Book a Free Damp Inspection in Bolton
If damp is rising above your DPC line, bridging may be the cause.
We’ll diagnose it properly and provide the right corrective work.
Book your free survey here:
https://weatherwiseuk.co.uk/pages/contact