Cavity wall insulation is designed to keep your home warmer — but when installed incorrectly or in the wrong type of wall, it can actually trap moisture and cause penetrating damp.
Across Wrexham, we’re seeing more and more homes suffering from damp, mould, and musty odours due to insulation bridging the cavity space.
💧 What Causes Cavity Wall Damp
The cavity in your wall acts as a barrier between the cold, wet outer layer and the warm inner wall. When this cavity is filled, insulation materials can soak up rainwater, transferring moisture directly into internal walls.
This problem is made worse when:
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Insulation is blown into cavities with pre-existing debris or moisture
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Walls are cracked or poorly pointed
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Properties are in exposed or coastal areas like parts of North Wales
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There’s no drainage path for moisture to escape
Once the insulation becomes saturated, it behaves like a sponge, pushing damp through to your plaster, causing dark patches, flaking paint, and eventually mould growth.
🔎 Signs of Damp from Cavity Insulation
If you live in or around Wrexham and have had cavity insulation fitted, look for these telltale signs:
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Damp or mould patches on internal walls, especially at low level
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Cold or “sweating” walls despite heating
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Musty smell or deteriorating plasterwork
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Visible staining on external brickwork
A professional borescope inspection can confirm whether your insulation is wet or has bridged the cavity.
🧰 Safe Methods for Repair
At Weather Wise Solutions, we work with accredited partners to safely remove failed insulation, clean out debris, and restore the cavity’s integrity.
Once cleaned, we ensure the wall is protected through:
✅ Repointing or repairing external cracks
✅ Applying breathable, water-repellent coatings
✅ Reinstalling only approved insulation systems if suitable
All work is carried out in line with the Federation of Damp standards, ensuring the wall remains dry, breathable, and structurally sound.
🏡 Protecting Your Wrexham Home
If you’ve noticed damp since insulation was installed, don’t ignore it. The longer moisture remains trapped, the greater the risk of hidden rot and internal damage.
👉 Book a cavity wall inspection today:
https://weatherwiseuk.co.uk/pages/contact