Penetrating Damp in London: Causes, Signs and Solutions
Penetrating damp is a common but serious issue that can affect property owners everywhere. Properties in London, however, are especially vulnerable because of the city’s high rainfall and the age of many buildings. If you think your property might have a penetrating damp issue, this post will let you in on some of the signs a PCA independent damp surveyor would use to diagnose it. We’ll also look at potential causes and solutions.
What is Penetrating Damp?
Unlike rising damp, which enters at the base of a building and travels upwards, penetrating damp travels horizontally, and it can begin anywhere above ground. All that’s needed is an exposed entry point on the outside of a building where water can get in. Like other damp issues, it can lead to mould, rot, unpleasant smells and unsightly walls or ceilings. In severe cases, it can render a building structurally unsound and harm occupants’ health.
Common External Causes
Independent damp surveys help property owners find the exact cause of penetrating damp. One common cause they find is an overflowing or broken gutter. This causes water to flow down the building’s walls, saturating the bricks and letting water inside. Cracks in walls, defective pointing and missing roof tiles also regularly turn out to be the cause, along with damaged or defective flashing around chimneys.
Key Signs to Look For
When an independent damp surveyor in London visits a property, they’ll usually begin with a visual inspection. During this process, they’ll be looking for clues that could indicate what type of damp they’re dealing with. The symptoms of penetrating damp can be similar to other types of damp, such as condensation, and they include mould, bubbling paint, flaking plaster and rotting skirting boards.
The location of these symptoms is often more of a clue than the symptoms themselves. If they appear on a wall that faces out of the property, this increases the odds that it’s penetrating damp. Condensation is also most likely to occur in kitchens and bathrooms, so symptoms outside of these make penetrating damp more likely. If they are more than a 1.5m above ground level, then rising damp can usually be ruled out.
Solutions for Penetrating Damp
Remedial action for penetrating damp usually consists of repairing the external defect that’s been letting water into the property, and fixing any internal damage that has already been caused. There’s no one-size-fits-all solution because each penetrating damp case has a different cause.
If you suspect your property has a penetrating damp problem, you should hire a PCA independent damp surveyor. They’ll pin down exactly what’s causing it and offer unbiased advice on how to fix it.
How Much Does an Independent Damp Survey in London Cost?
Independent damp surveys in London range from £150 upwards, depending on location, reputation, PCA-membership, and so on. Contractors who sell damp treatments tend to offer lower priced surveys, but may convince you to spend money on unnecessary treatments or products.
Conclusion
If you’ve spotted signs of penetrating damp in your property, it’s important to stop it before it’s able to progress. Call London Damp Specialists on 020 7523 5882 to inquire about an independent damp survey today.
Damp Survey Costs
Transparent pricing with no hidden fees for our independent, unbiased surveys.
Level 1
What’s included:
- Inspection of walls
- Inspection of floors
- Inspection of ceilings
- Leak inspection of drains and plumbing
- Damp information and prevention guide
Level 2
What’s included:
- Everything in Level 1
- Dry rot inspection
- Wet rot inspection
- Woodworm inspection
- Damp information and prevention guide
Level 3 (Most Popular)
What’s included:
- Thermal Imaging
- Air humidity testing
- HD boroscope camera
- Brickwork pointing inspection
- DPC inspection
- Ventilation flow test on extractor fans
- 4K drone imagery roof, chimney stack
and guttering inspection - Structural condition inspection
- Inspection of walls
- Inspection of floors
- Inspection of ceilings
- Leak inspection of drains and plumbing
- Dry rot inspection
- Wet rot inspection
- Woodworm inspection
- Damp information and prevention guide
Survey Add Ons
Add On 1
Laboratory analysis Of plaster identifies hygroscopic salts such as chlorides and nitrates. which indicate whether damp is caused by rising groundwater or by plumbing leaks, This testing removes guesswork, allowing the exact source of moisture to be identified so the correct treatment is applied rather than carrying out unnecessary damp-proofing work.
Add On 2
qPCR DNA mould testing detects microscopic mould spores that are invisible during a normal inspection and van remain hidden behind walls, floors. or inside building rkaterials. It identifies the exact mould species present and the contamination level, allowing hidden mould problems to be confirrned and properly treated before they affect the property or occupants’ health.
Qualifications: All our surveyors are PCA and CSRT qualified for remedial treatments and also CSSW qualified for structural waterproofing.
Next day report: You will receive the report within 24 hours of the inspection taking place.
The survey fee will be deducted from the cost of any recommended repairs.
These are the tools we use
Damp Meter
A damp meter is a diagnostic tool used to detect and measure moisture levels within building materials such as plaster, brick, timber, and concrete.
Borescope camera
borescope camera is a small inspection camera attached to a flexible semi-rigid cable that allows you to see inside areas that are otherwise inaccessible.
Drone Inspection
A drone is a remotely operated aerial device equipped with a camera that allows visual inspection from above without the need for scaffolding or ladder.
Air Humidity Sensor
Air humidity sensor measures the amount of moisture present in the air, expressed as relative humidity (RH) in percentage. It helps determine whether indoor conditions are contributing to condensation, mould growth, or damp-related issues.
Thermal Imaging Camera
A thermal imaging camera detects temperature differences on surfaces by using infrared technology to produce a heat map image. In damp investigations, it helps identify cold spots, moisture intrusion, insulation defects, thermal bridging and leaks.
Air Flow Ventilation Detector
An air flow ventilation detector measures the movement and volume of air passing through vents, extractor fans, and air bricks. It confirms whether ventilation systems are working properly and achieving adequate air changes within a room. Poor airflow leads to trapped moisture, high humidity, condensation on cold surfaces, and ultimately mould growth.
Mould Lab Swab Testing
A mould swab test is carried out to confirm the presence of hidden mould growth and identify the specific species involved. Surface mould is not always visible, especially behind furniture, inside cavities, or within ventilation systems. Laboratory analysis of a swab sample determines whether active mould spores are present and what type they are, which helps assess potential health risks and decide the correct remediation approach rather than relying on visual assumption alone.
Lab Analysis of Plaster
Laboratory analysis of plaster is used to identify the type of salts present within the material, typically chlorides and nitrates. The presence and concentration of these salts help determine whether the moisture source is consistent with rising damp, ground contamination, or another forms [sic] of water ingress. such as mains water leak, This removes guesswork and prevents misdiagnosis, ensuring the correct remedial treatment is specified rather than applying unnecessary or ineffective solutions.
