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What Is Penetrating Damp?
Penetrating damp is caused by water leaking through external walls, roofs or structural detailing and saturating the internal fabric of a building. Unlike rising damp, which travels upward from the ground, penetrating damp enters horizontally through defects in the building’s external envelope.
It’s especially common in older properties, where solid walls, lime mortars, or ageing masonry are more exposed to prolonged weathering — and modern alterations may have restricted natural breathability.
Common Causes of Penetrating Damp:
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Cracked or damaged render
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Failed pointing or degraded mortar joints
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Damaged brickwork or porous stone
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Defective roof coverings or flashing
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Blocked or leaking gutters, downpipes or hoppers
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Bridged cavity walls (where debris allows water to track across)
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Inappropriate paint or waterproof coatings that trap moisture
Penetrating damp can lead to internal staining, black mould, timber decay, and long-term structural deterioration if left unresolved.
At Bramley & Stone, we don’t just mask the symptoms — we trace the source of water ingress, repair the defect with breathable, sympathetic materials, and ensure the building is properly protected while maintaining its period character.
Trusted Penetrating Damp Specialists
At Bramley & Stone, we’re known for our ability to diagnose and resolve penetrating damp in a way that respects the age, structure, and materials of your home.
Unlike general contractors or quick-fix builders, we specialise in treating moisture ingress in period and heritage properties — where breathability, traditional finishes, and sympathetic repairs matter most.
Why homeowners trust Bramley & Stone:
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Survey-led approach – Every treatment starts with a professional damp survey to identify the true source of water ingress
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Expert knowledge of traditional buildings – We understand how older structures respond to moisture and avoid modern materials that trap damp
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Repairs done properly – Whether it’s repointing with lime mortar, replacing defective render, or repairing failed flashing, our work is carried out to a conservation standard
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Discreet, professional workmanship – Our team respects your home and leaves it protected, clean, and dry
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Transparent quotations & guaranteed work – No pressure sales, no vague advice — just honest recommendations backed by experience
Whether you’re dealing with visible water stains, persistent mould, or an ongoing leak no one else can trace, we’ll provide a complete and permanent solution.
What Causes Penetrating Damp?
Penetrating damp is caused by external water finding its way through the fabric of a building, often due to ageing materials, defective detailing, or poorly executed modern repairs. It tends to affect walls, ceilings and structural timber — especially in exposed or weather-facing areas.
This type of damp is especially common in solid-walled period properties, where there is no cavity to stop water from tracking through to internal surfaces.
The Most Common Causes of Penetrating Damp Include:
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Cracked or damaged render – Water seeps through failed external coatings, especially where modern cement render has trapped moisture underneath
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Degraded pointing or mortar joints – Worn-out or cement-based mortar allows rainwater to soak into masonry
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Defective guttering or downpipes – Overflowing or leaking rainwater goods direct water onto external walls
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Faulty or missing flashing – Roof junctions, chimney stacks, and bay windows are vulnerable to driving rain without properly installed leadwork
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Blocked or bridged cavities – In cavity wall properties, debris inside the cavity allows water to cross into internal walls
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Non-breathable paints or sealants – Modern waterproof coatings can trap moisture within walls, forcing it to escape internally
Period properties are especially vulnerable, as solid brickwork and lime mortars are natur
How can you recognise penetrating damp in the house?
Penetrating damp often appears slowly and affects isolated areas — especially external walls, ceilings, or corners where water can enter from outside. Unlike rising damp, which appears uniformly at low levels, penetrating damp is usually patchy and linked to external defects.
Common Signs of Penetrating Damp:
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Damp patches on internal walls or ceilings, often discoloured and irregular in shape
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Mould growth in isolated areas, particularly near windows, chimney breasts, or under flat roofs
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Peeling paint or wallpaper, especially on upper walls or ceilings
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Cold, damp spots in rooms that feel noticeably different to the surrounding area
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Water ingress after heavy rain, often appearing days later as the wall slowly becomes saturated
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Rotting timbers near the source of ingress — e.g. window frames, roof timbers, or floor joists
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Flaking plaster or blown finishes that sound hollow when tapped
These symptoms are more common in wind-exposed elevations, older properties with weathered brickwork, or homes with poorly maintained render or pointing.
If left untreated, penetrating damp can lead to timber decay, heat loss, and long-term structural damage. That’s why a professional survey is crucial — not just to identify the visible signs, but to trace the underlying cause.
How do you treat penetrating damp?
The common signs and symptoms of penetrating damp to look out for include the following:
- Visible damp stains on external walls
- Damp patches on ceilings (it may darken when it rains)
- Signs of fungal spores concentrated in an area
- Wet and crumbly plaster
- Drips and puddles
- Patches formation walls or ceilings
- Moist and disintegrating plasterwork
- Evidence of dark mould
- Growth of moss and algae on the exterior walls
- Leaky or overfilled gutters or drainpipes
If you happen to spot any of the above signs on your property, then you have a penetrating damp problem
Contact Our Local Experts For Penetrating Damp
Expert Solutions for a Damp-free, Healthier Home
Are you looking for a reliable Penetrating Damp Specialist to get rid of your damp issues? Our team of local damp-proofing specialists has some effective solutions to help you eliminate penetrating damp. Tackling damps requires different approaches for every property comes with unique features. We conduct professional damp surveys to identify the source and offer the best damp-proofing treatment.
Contact us at 0800 080 6062 and get rid of penetrating damp now!
Penetrating Damp Treatment
For reliable Penetrating Damp Treatment contact us today and rectify any existing defects promptly.
