Penetrating damp and rising damp: what is the difference and why does it matter for a claim?

When you report damp to your landlord, they may respond by saying the damp is "condensation" or a "lifestyle issue" and not their problem. Or they may say there is penetrating damp but dispute the source. Understanding the types of damp helps you challenge these arguments confidently.

Key facts

• The 2024 to 2025 English Housing Survey found serious condensation (3% of homes) was more common than penetrating damp (2%) or rising damp (1%). English Housing Survey 2024-25, GOV.UK
• The same survey found about 5% of homes in England, around 1.4 million, had a problem with damp, most common in privately rented homes (10%). English Housing Survey 2024-25, GOV.UK

The three main types of damp

1. Condensation damp

Condensation occurs when warm, moist air meets a cold surface, usually external walls, windows, or cold corners, and water droplets form. In poorly insulated or poorly ventilated homes, condensation can cause mould on walls, ceilings, around windows, and in wardrobes.

Landlords sometimes argue that all mould is condensation and that condensation is the tenant's fault (because of cooking, drying washing, or not ventilating enough). This argument is frequently incorrect.

Condensation mould in a well-occupied home with normal use is very often caused by structural deficiencies: inadequate insulation, cold bridging, poor ventilation, or insufficient heating. Courts and legal proceedings have repeatedly rejected the "tenant's lifestyle" explanation where the property's structure was the underlying cause.

2. Penetrating damp

Penetrating damp occurs when water enters the building from outside through defective elements: a leaking roof, cracked external render or brickwork, damaged pointing, defective guttering, blocked drains, or leaking window frames. It usually appears as localised wet patches or staining on walls, particularly following rain, and the location often corresponds to a specific external defect.

Penetrating damp is almost always the landlord's responsibility. It arises from a structural or maintenance failure that the tenant cannot address. Section 11 of the Landlord and Tenant Act 1985 explicitly includes "the structure and exterior of the dwelling" within the landlord's repair duty.

3. Rising damp

Rising damp occurs when groundwater travels upward through masonry due to capillary action, typically because a damp-proof course is absent, has failed, or has been bridged by raised ground levels. It appears as a tidemark on lower walls, often with salting and crumbling plaster.

Rising damp is less common than condensation or penetrating damp, though it is sometimes diagnosed incorrectly. Like penetrating damp, it is a structural issue and the landlord's responsibility.

How landlords use the condensation argument

When a landlord says "it's just condensation", they may be trying to avoid repair responsibility by framing the problem as a behavioural issue. Common variations:

• "You need to open windows more often"
• "You should not dry washing indoors"
• "The mould is because you are cooking a lot"
• "If you heated the property more, you would not have this problem"

These statements may have some truth in extreme cases, but in a normally occupied home with adequate insulation and ventilation, they are often incorrect. The key question is whether the structural condition of the property enables normal residential occupation without mould.

How to challenge the "it's condensation" argument

1. Commission an independent damp survey. A RICS-qualified surveyor can identify the type of damp, its cause, and whether the building's condition is contributing to it. This is stronger evidence than your landlord's own contractor.

2. Document the location and pattern. Penetrating damp appears after rain and on external walls. Rising damp appears at low levels. Condensation appears on cold surfaces in warm rooms. Photographs with dates help establish the pattern.

3. Note the moisture readings. A damp meter reading from an independent surveyor shows the extent of moisture in the building materials, not just on the surface.

4. Challenge the landlord's contractor's diagnosis in writing. If your landlord sends someone who attributes the damp to condensation without inspecting the external structure, write back asking them to explain specifically why they have ruled out penetrating damp or rising damp and what structural investigation they carried out.

5. Ask for an HHSRS inspection. Environmental health will assess the property under the Housing Health and Safety Rating System. Damp and mould is a Category 1 hazard when it represents a significant risk of harm to health.

Why the type of damp matters in a claim

The type of damp affects who is responsible and how much the repair costs. If the damp is penetrating, caused by a failing roof or cracked render, the landlord must fix the external structure. If the landlord has instead been treating surface mould repeatedly without addressing the structural cause, they may be carrying out cosmetic rather than proper repairs, and each recurrence of mould adds to the period of disrepair for which compensation is calculated.

When should I contact Support for Tenants?

If you have persistent damp or mould that keeps returning, call us on 0800 030 4669.

No upfront cost. You only pay if you win, and the fee comes out of the compensation, not your pocket. If you don't win, you pay nothing.

Sources

• Section 11, Landlord and Tenant Act 1985 (legislation.gov.uk)
• Housing Health and Safety Rating System (HHSRS) guidance (GOV.UK)

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• My landlord painted over the mould, is that a proper repair?
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