Penetrating Damp

What is Penetrating Damp?

Penetrating damp — also known as lateral damp — is caused by water making its way through the external fabric of a building. Unlike rising damp, which travels upwards from the ground, penetrating damp can occur at any level of the property and is often the result of external defects or maintenance issues.

It can affect walls, ceilings, and floors, especially during periods of heavy rainfall or prolonged damp weather.

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What Causes Penetrating Damp?

Common causes include:

• Defective or porous brickwork

• Damaged or missing roof tiles

• Blocked or broken gutters and downpipes

• Cracked render or pointing

• Faulty window seals or door frames

• Bridged damp-proof courses

Once water gets in, it can cause lasting damage if not properly identified and resolved.

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Signs of Penetrating Damp

Look out for:

• Damp patches on internal walls or ceilings

• Localised staining that darkens after rain

• Peeling paint or blistering plaster

• Mould growth in isolated areas

• Water ingress around windows, chimneys, or corners

• Damp smells in rooms near external walls

These signs may appear gradually or suddenly after a heavy downpour.

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How We Diagnose Penetrating Damp

A correct diagnosis is key — penetrating damp is often misidentified as condensation or rising damp. As independent surveyors, we carry out a detailed, unbiased investigation to determine the true cause.

Our survey may include:

• External and internal inspection of problem areas

• Moisture profiling using meters

• Thermal imaging to trace cold spots and water paths

• Inspection of rooflines, rainwater goods, and pointing

• Access camera surveys for hard-to-reach voids

We’ll also check for signs of overlapping damp issues (e.g. condensation + external defects) and recommend targeted solutions.

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Independent, Honest Advice You Can Trust

We do not sell damp treatments, so our advice is always based on what’s genuinely needed — not what someone wants to sell you.

You’ll receive:

• A tailor-made report

• Clear identification of the cause

• Practical repair recommendations

• Peace of mind, with no sales pressure

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Book a Penetrating Damp Survey

Whether you’re a homeowner, buyer, landlord or contractor, our surveys are tailored to your needs — from minor issues to full building assessments.

Contact us today to book your survey and get expert insight into your property’s condition.