Damp Investigation

Damp Source Investigation London

When you can see damp but do not know the cause, we investigate externally to find the source and recommend practical repairs.

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Understanding Damp

Symptom vs Source

Damp patches, staining, peeling paint and mould growth are symptoms. They tell you water is present, but they do not tell you where it is coming from. The source could be a roof defect, failed pointing, blocked gutter, defective flashing, or any number of external failures that allow water into the building envelope.

When visible damp appears internally, the problem is already established externally. The external defect has been active long enough for water to penetrate through to the internal surface. Internal decorating alone does not solve this. Without fixing the source, the damp will return every time it rains.

Many landlords invest in internal treatments, damp surveys that only look inside, or repeated redecoration without ever addressing the external cause. This is costly and ineffective because the source remains active. The correct approach is to investigate externally first, find the defect, and repair it.

Saturated walls take considerable time to dry even after the source is resolved. The longer the external defect persists, the deeper the masonry saturation and the longer the eventual drying period. Early investigation and repair is consistently cheaper than allowing the problem to worsen.

External Causes

Common External Causes of Damp

Failed Pointing

Eroded mortar joints allow rain penetration through the wall, particularly on exposed elevations.

Gutter Overflow

Blocked or failed gutters discharge water onto the wall below, saturating the masonry over time.

Roof Defects

Slipped tiles, failed flashings or flat roof splits allow water into the building structure from above.

Parapet Failures

Open coping joints and failed parapet pointing allow water to enter from the top and track downward.

Window and Lintel Defects

Failed sealant, defective sills or cracked lintels create localised water entry points at openings.

Downpipe Leaks

Cracked or disconnected downpipes discharge rainwater directly onto the wall face instead of into drains.

Our Process

How We Investigate Damp Sources

1

Internal Assessment

We look at where and how the damp presents internally to understand the likely external source area. The pattern, location and behaviour guide our external investigation.

2

External Investigation

We inspect the external envelope at close range, focusing on the areas that correlate with the internal symptoms. Rope access allows inspection of high-level areas without scaffolding.

3

Source Identification

We identify the specific defect or defects responsible for the water entry and document them with clear photographs and explanations.

4

Repair or Report

Where repairs are straightforward, we carry them out during the same mobilisation. For larger works, you receive a clear report with repair recommendations and costs.

Related services: Water Ingress Investigation Top Floor Damp External Defect Investigation All Landlord Services
FAQ

Frequently Asked Questions

Many damp surveys only look inside the property and measure moisture levels without investigating the external source. We focus on the external envelope because that is where the cause almost always lies. Finding and fixing the source is more effective than treating symptoms internally.
Because the external source has never been addressed. Internal decorating hides the symptom temporarily but does not stop water entering the wall from outside. Until the external defect is found and repaired, the damp will continue to return after every period of rain.
Saturated walls take time to dry depending on wall thickness, ventilation and how long the problem persisted. Typical drying times range from several weeks to several months. Thicker solid walls and deeply saturated masonry take longer. We can advise on expected timescales for your situation.
In most cases, yes. Our experience with London building types means we can correlate internal symptoms with likely external causes efficiently. In complex cases with multiple potential sources, we may recommend targeted water testing to confirm the primary entry point.
Get Started

Damp But Don't Know the Cause?

Stop treating symptoms and start fixing sources. Get in touch for an external investigation that identifies the real cause of your damp problem.

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