Damp and wetness seeping through the wall

How to Treat Penetrating Damp?

Key Takeaways

Common Causes of Penetrating Damp: Leaking roofs, faulty gutters, cracked masonry, defective window seals, damaged flashings, porous building materials, external wall defects, landscaping issues.

Signs Indicating Penetrating Damp: Damp patches, staining, peeling paint, dampness after rainfall, mold growth, water streaks, decayed skirting boards, deteriorating plaster, musty odor, efflorescence.

Standard Treatment Methods: Identify and repair roof leaks, maintain gutters, seal cracks, improve window and door seals, repair flashings, use exterior waterproof coatings, install cavity trays, address external drainage issues, make landscaping adjustments, consider interior drainage systems and damp-proof membranes.


Penetrating damp is basically water ingression, and it has the potential to cause a lot of damage to the structures wherever it is present. This issue can get serious if left untreated, can cause irreparable harm to the house, and can also cause harmful health hazards to the family members.

In simpler terms, when a penetrating damp situation occurs, moisture enters the house from through its external walls, roof, or below-ground areas. It can be witnessed when visible patches start appearing on the affected areas.

Also, other signs of penetrating damp might include peeling wallpaper, bubbling plasterwork, flaking of wall surfaces, mould growth, musty smells all around the house, and visible structural damage in the home.

Before the above signs turn into something serious, which can even be life-threatening, the issues of penetrating damp must be resolved. It should be treated at any cost. As there are many treatment options available, it’s not that hard to treat it. Let’s see what these treatment options are.


Peeling plaster work due to damp


What Exactly is Penetrating Damp?

Penetrating damp is caused by water entering a building and spreading horizontally through walls, ceilings, or floors.

Unlike rising damp that moves upward from the ground, penetrating damp comes from external sources. It can cause problems like damage to the building, material decay, and the risk of mould growth.


Rising damp on a wall


What are the Common Causes of Penetrating Damp?

Common causes of penetrating damp include:

Leaking Roofs

Damaged or missing roof tiles, cracked roof flashing, or compromised roof coverings can allow rainwater to penetrate and enter the building.

Faulty Gutters and Downspouts

Blocked or damaged gutters and downspouts can lead to water overflowing and running down the exterior walls. This water can then penetrate the building fabric.

Cracked Masonry or Brickwork

Cracks in the external walls, pointing issues, or damaged brickwork can provide pathways for water to penetrate into the building.

Faulty Window and Door Seals

Poorly sealed windows and doors can allow rainwater to infiltrate, especially during heavy rainfall or when exposed to driving winds.

Defective Flashings

Inadequate or damaged flashings around windows, doors, chimneys, and other structural elements can allow water to seep into the building.

Porous Building Materials

Some building materials, such as porous bricks or stonework, can absorb water and transmit it through the structure, leading to dampness.

External Wall Defects

Cracks, gaps, or defects in the external walls, including mortar joints, can provide direct pathways for water to enter the building.

Landscaping Issues

Poorly designed or maintained landscaping, such as flower beds or raised ground levels against external walls, can contribute to penetrating damp by allowing water to accumulate against the building.


Penetrating damp and moisture on ceiling


What Signs Indicate Penetrating Damp?

Penetrating damp occurs when water enters a building from outside, and early recognition of signs is vital to address and prevent further damage. Common signs include:

Damp Patches on Walls or Ceilings

Horizontal damp patches that spread across walls or ceilings are a common sign of penetrating damp. These patches are often darker in colour and may appear after rainfall or during wet weather.

Staining or Discoloration

Staining or discolouration of internal decorations, such as paint or wallpaper, is indicative of water ingress. The presence of water can cause these materials to change colour or appear damp.

Peeling or Blistering Paint and Wallpaper

Penetrating damp can lead to the deterioration of paint and wallpaper. Look for peeling, bubbling, or blistering, especially along the affected areas.

Dampness Following Rainfall

If dampness is more pronounced after rainfall or during wet weather, it suggests that water is entering the building from the outside. It is a crucial indicator of penetrating dampness.

Mold and Mildew Growth

The presence of mould or mildew on walls, ceilings, or other surfaces is often associated with damp conditions. Penetrating damp provides the moisture necessary for mould and mildew to thrive.

Visible Water Streaks

Water streaks or tracks running down walls or across ceilings can be visible signs of water penetration. These streaks may appear darker than the surrounding areas.

Decayed or Damaged Skirting Boards

Skirting boards, particularly those at the base of walls, may show signs of decay or damage due to prolonged exposure to moisture from penetrating damp.

Deterioration of Plaster

The plaster on walls may show signs of deterioration, including crumbling or softening, as a result of water penetration. Check for changes in the texture and condition of the plaster.

Musty Odor

Penetrating damp can contribute to a very musty smell or damp odour in affected areas. This smell is often a result of mould growth or the presence of stagnant water within the building.


Efflorescence is the crystalline deposit of salts on surfaces due to the evaporation of water. It appears as white, powdery deposits on walls and is a common sign of moisture penetration.


Moisture damp on a wall


Standard Methods to Treat Penetrating Damp

Dealing with penetrating damp requires finding and fixing the source of water entry to avoid more damage and damp-related problems. The chosen method depends on the cause and severity of the issue. Common damp treatments can include:

Identify and Repair Roof Leaks

Inspect the roof for damaged or missing tiles, cracked flashings, and other issues. Repair or replace any damaged roofing materials to prevent rainwater from entering the building.

Maintain Gutters and Downspouts

Clean gutters regularly to prevent blockages and ensure that downspouts direct water away from the building. Repair or replace damaged gutters and downspouts to improve drainage.

Seal Cracks and Gaps

Identify and seal any cracks or gaps in the external walls, including around windows, doors, and other openings. Use appropriate sealants to create a watertight barrier.

Improve Window and Door Seals

Ensure that windows and doors are correctly sealed to prevent water ingress. Replace damaged or worn seals, and consider installing weatherstripping to enhance the seal.

Repair Flashings

Inspect and repair flashings around chimneys, windows, doors, and other structural elements. Adequate flashing prevents water from penetrating through gaps or vulnerable areas.

Exterior Waterproofing Coatings

Apply waterproof coatings to external and interior walls to create a protective barrier against moisture. These coatings can help repel water and prevent it from penetrating the building fabric.

Install Cavity Trays

Cavity trays are installed above openings in walls, such as windows and doors, to direct water away from vulnerable areas. They help prevent water from entering the building through these openings.

External Drainage Systems

Install external drainage systems to redirect surface water away from the building. It helps minimize the risk of water accumulating against exterior walls.

Landscaping Adjustments

Ensure that the ground around the building slopes away from the foundation. Avoid creating raised flower beds or other landscaping features that can trap water against the external walls.

Interior Drainage Systems

In severe cases, installing an interior drainage system along the basement perimeter can help manage water ingress. It involves creating a channel or trench that directs water to a sump pump for removal.

Damp-Proof Membranes

Use damp-proof membranes on walls and floors to create a barrier against moisture. These membranes can be applied internally or externally, depending on the specific circumstances.


House surveyor surveying a house


How to Prevent Penetrating Damp?

Preventing penetrating damp is a series of proactive procedures aimed at protecting a structure from external moisture intrusion. Regular maintenance, beginning with the roof, is one of the most important tactics. It is critical to inspect the ceiling for broken or missing tiles, degraded flashings, and other hazards.

You may reduce the chance of precipitation entering the structure and producing penetrating damp by addressing any concerns that are discovered as soon as possible, such as leaks or damaged roofing materials.

Another essential part of prevention is ensuring that gutters and downspouts work correctly. Cleaning gutters on a regular basis to remove debris and avoid obstructions guarantees adequate water drainage.

Furthermore, keeping downspouts in good condition and diverting them away from the building foundation helps to keep water from pooling against external walls, minimizing the probability of water penetration.

Water ingress can be prevented by sealing cracks, gaps, and holes in the building envelope. Using proper sealants around windows, doors, and other vulnerable locations forms a moisture barrier, improving the building’s resistance to entering wet.

Effective exterior wall waterproofing coatings give an extra element of security. When these coatings are applied to exterior walls, they create a barrier that repels water and lowers the danger of moisture infiltration.

Cavity trays, strategically placed above openings such as windows and doors, deflect water away from susceptible locations, preventing it from seeping into the building structure.

A preventive maintenance program must include regular inspections and rapid fixes. Checking the exterior of the structure on a regular basis for signs of wear, cracks, or degradation provides for early detection of possible weaknesses.

Addressing these concerns as soon as possible prevents them from worsening and leading to water infiltration and penetrating wet.


Peeling of paint work due to rising damp


Is Penetrating Damp Harmful for Health?

Musty smells and damp appearances may be unpleasant, but addressing penetrating damp promptly minimizes health risks. Prolonged exposure to damp conditions is unhealthy and demands immediate resolution.

Severe penetrating damp can result in condensation and black mould growth, leading to health problems like allergies. Ugly black mould spots attract germs and microbes, causing additional health issues. Swiftly addressing these concerns is crucial.


Bubbling of plaster on a wall due to damp


How Much Does it Cost to Treat Penetrating Damp?

How expensive is penetrating damp treatment? The cost varies based on the severity and size of the affected area. Treatment for severe penetrating damp problems caused by porous building materials may involve using damp protection creams.

Minor repairs can be relatively inexpensive, while professional jobs, including protection, damp proofing, and plasterwork, can be more costly. The repair expenses also depend on the specific fixes needed, as there is no one-size-fits-all solution for penetrating damp issues.


Damp moisture on a wall


Does a Home Insurance Cover Penetrating Damp?

In most cases, insurance won’t cover penetrating damp, mainly if it’s caused by property maintenance issues.

Home insurance typically doesn’t cover building defects resulting from the property owner’s responsibility to maintain the building.

Damage from wear and tear, like a damaged roof, is the owner’s responsibility for maintenance costs. However, if there’s a specific event like a storm or fire, the homeowner can file a claim with the insurance company.



Why Get a Penetrating Damp Survey?

Conducting a penetrating damp survey is crucial for various reasons. It helps identify issues in a building’s structure, especially where water may be entering.

By examining the roof, walls, windows, and doors, surveyors can find vulnerabilities and signs of dampness.

The survey is essential for diagnosing the specific causes of penetrating damp, such as leaks or structural problems.

A significant benefit of the survey is receiving personalized solutions based on its findings. Professionals can suggest measures like roof repairs, gutter improvements, sealing cracks, or applying waterproof coatings.


How is a Penetrating Damp Survey Carried Out?

It’s crucial to hire a specialist for a damp survey on your property to identify and address any penetrating damp issues.

Damp Surveyors Ltd. employs surveyors fully qualified by the Property Care Association, specifically as Certified Surveyors in Remedial Treatment (CRST).

Our experts are highly trained to offer solutions for various penetrating damp problems affecting your property.

After the inspection, our surveyor will provide a detailed report outlining the causes of the issues and the necessary treatments to fix the penetrating damp problem.


Call Us Now for a Penetrating Damp Survey

Finding and addressing penetrating damp early is crucial for preventing severe damage to your property and maintaining its long-term integrity. If you suspect dampness, it’s essential to act promptly.

At Damp Surveyors Ltd., we offer specialized services to identify and assess penetrating damp in homes or businesses. Early detection allows for targeted interventions, preventing the penetrating damp issue from becoming more serious.

Contact our specialists at 0330 053 3432 to benefit from our expertise and comprehensive survey services. Our team can thoroughly inspect, identify root causes, and provide recommendations for effective treatment and prevention.

We understand the urgency of damp issues, and our prompt and efficient services are tailored to your property’s specific needs.


How do you get rid of penetrating damp?

To stop dampness, find and fix where water is getting in. Check the outside for cracks, broken roof tiles, or gaps in windows and doors. Repair any issues and seal them well. Use water-resistant coatings outside, and treat affected walls inside with waterproofing solutions. Ensure good ventilation to reduce condensation. Get professional advice for a thorough assessment and tailored solutions.

How serious is penetrating damp?

Penetrating damp is a serious problem that can damage structures, harm building materials, and promote mold growth. If not dealt with, it can weaken walls and cause lasting harm to a property. Additionally, dampness can worsen respiratory issues and allergies, posing health risks. Taking prompt action is essential to prevent further problems and reduce potential risks to both the structure and health.

Is penetrating damp expensive to fix?

Fixing penetrating damp can have varying costs based on damage extent, underlying causes, and needed repairs. It’s recommended to address the issue promptly to prevent increased damage and costs. Expenses usually include identifying and fixing water penetration sources, repairing damaged materials, and implementing preventive measures. Although costs differ, investing in professional assessment and repairs is often cost-effective in the long run, preventing further deterioration and potential health hazards from dampness.

Table of Contents

Picture of Sam Fitzgerald – CSRT Damp Surveyor

Sam Fitzgerald – CSRT Damp Surveyor

Author – CSRT Damp Surveyor
Sam is a highly qualified and seasoned damp surveyor with over ten years of specialised experience. With a strong academic foundation in building surveying and numerous professional certifications, Sam has established himself as an authority in the field of damp diagnosis and remediation.

At Damp Surveyors Ltd, Sam applies his extensive knowledge to help homeowners across the UK address and solve their damp issues effectively. His approach combines cutting-edge techniques with a commitment to honest, client-focused service, ensuring that every survey and recommendation is tailored to the specific needs of the property.

As a thought leader, Sam’s insights into damp prevention and treatment have been featured in industry publications, underscoring his role as a trusted expert dedicated to maintaining the integrity and comfort of your home.

Testing device for measuring dampness in a house


At Damp Surveyors Ltd, we stand out as your premier choice for damp survey services in the UK. Our commitment to excellence and customer satisfaction sets us apart. Here’s why you should choose us:

  • Exclusive 3 Free Quotes: We offer a one-of-a-kind optional service where you not only get our top-notch damp survey but also receive 3 free quotes from vetted local companies, giving you peace of mind by saving you thousands on getting the most competitive quotes, and also time researching and contacting other reputable companies.
  • Knowledge and Experience: We provide unmatched knowledge to every survey we conduct thanks to our team of seasoned professionals and years of industry experience. This guarantees accurate assessments and practical solutions.
  • Nationwide Coverage: Whether you’re in a bustling city or a rural area, our services extend across the UK, making us accessible wherever your property is located. Choose us for nationwide reliability and excellence.

Choose Damp Surveyors Ltd as your reliable partner for all-inclusive survey needs. Our top concerns are the health and safety of your property, and we are committed to providing outcomes you can trust.

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