Rising damp is a common but often misdiagnosed problem in UK homes. It occurs when moisture from the ground moves up through porous walls, affecting brick, plaster, and timber. If left untreated, it can cause serious structural damage, create an unhealthy indoor environment, and increase heating costs. Many homeowners mistake it for condensation or penetrating damp, leading to incorrect treatments and unnecessary expenses.
One of the biggest risks of rising damp is that it develops slowly over time. Initially, it may appear as a damp patch near skirting boards, but as moisture continues to rise, paint peels, wallpaper bubbles, and salt deposits appear. Eventually, it can weaken walls, rot flooring, and contribute to mould growth, making your home uncomfortable and harder to sell.
Beyond property damage, damp conditions can worsen respiratory problems, particularly in children, the elderly, and those with asthma. With energy prices rising, damp walls reduce insulation efficiency, meaning you’ll pay more to heat your home.
The key to managing rising damp is early detection and an accurate diagnosis. A professional damp survey is essential, as different companies may only recommend treatments based on what they sell, rather than what your property actually needs. Home Energy Save GB provides a full, independent assessment covering all damp-related issues, ensuring homeowners get the correct diagnosis and avoid unnecessary repairs.
This guide will cover:
- What rising damp is and how to identify it
- The most common causes of rising damp
- The importance of accurate diagnosis
- Effective treatment and prevention strategies
By understanding rising damp and getting a professional survey, you can protect your home, avoid unnecessary costs, and maintain a healthy living environment.
What is Rising Damp?
Rising damp is a form of moisture ingress that occurs when water from the ground is drawn up through a building’s walls by capillary action. Porous materials such as brick, plaster, and timber absorb moisture, allowing it to travel upwards.
Unlike condensation, which forms due to excess indoor humidity, or penetrating damp, which results from external leaks, rising damp originates from the ground and moves vertically.
Most modern homes have a damp proof course (DPC) to act as a barrier against moisture. This is typically made from slate, plastic, or bitumen. However, if the DPC is missing, damaged, or bridged by external materials, water can rise unchecked, leaving visible signs of damp.
Key Features of Rising Damp
- Tide marks – Brown or yellowish stains up to one metre high on walls
- Salt deposits – White, powdery residue from moisture evaporating
- Peeling wallpaper & blistering paint – Caused by moisture weakening adhesives
- Rotting skirting boards & flooring – Damp timber can crack, warp, or soften
- Musty smell & damp patches – Often in poorly ventilated areas
Rising damp rarely extends higher than a metre due to gravity and evaporation. However, if walls are covered with non-breathable materials, such as vinyl wallpaper or cement-based plaster, moisture can become trapped, causing damp to spread further.
Why Professional Diagnosis Matters
Because rising damp shares symptoms with other damp issues, it is frequently misdiagnosed. Getting a professional survey from Home Energy Save GB ensures an accurate assessment, preventing ineffective treatments and unnecessary expenses. HES evaluates the entire property—not just isolated symptoms—so homeowners get the correct diagnosis and the most effective long-term solution.
Signs of Rising Damp
Spotting early signs of rising damp is crucial to preventing structural damage and unnecessary costs. Because rising damp starts at the ground level and moves upwards, symptoms typically appear at the base of walls, up to one metre high.
How to Identify Rising Damp
- Peeling wallpaper or blistering paint – Moisture weakens adhesives, causing bubbling or flaking.
- Tide marks & salt deposits – As damp evaporates, it leaves white, powdery salt residue that attracts moisture from the air, keeping walls damp.
- Rotting skirting boards & flooring – Prolonged moisture exposure can cause wood to warp, crack, or decay.
- Persistent damp patches & musty smell – Unlike condensation, which dries with ventilation, rising damp remains and worsens over time.
Many homeowners mistake rising damp for condensation or penetrating damp, leading to incorrect treatments that don’t solve the issue. Some companies may only offer solutions that align with their product range, resulting in ineffective or unnecessary repairs.
Home Energy Save GB (HES) conducts comprehensive damp surveys, covering all possible causes—including chimney leaks, external wall issues, and ventilation concerns—to give an accurate diagnosis and prevent costly mistakes.
If you notice any signs of damp, it’s essential to get a professional survey before committing to any treatment.
Causes of Rising Damp
Rising damp occurs when moisture from the ground is drawn up through porous walls due to capillary action. While a damp proof course (DPC) is designed to block this moisture, several factors can compromise its effectiveness, allowing water to rise unchecked.
Common Causes of Rising Damp
- Failed or Missing Damp Proof Course (DPC)
Most homes have a DPC made of slate, plastic, or bitumen to prevent moisture from rising. However, in older properties, particularly those built before the 20th century, the DPC may be missing or deteriorated. Cracks or damage in an existing DPC allow moisture to bypass the barrier, leading to rising damp.
- High External Ground Levels
If soil, paving, or driveways are higher than the DPC, moisture can bridge the barrier, making the DPC ineffective. This is common in homes where patios, flower beds, or pathways have been built up over time without considering damp protection.
- Poor Drainage Around the Property
Blocked gutters, downpipes, or surface drains can cause water to pool around the foundations, increasing the risk of moisture seeping into walls. Sloping ground that directs rainwater towards the property rather than away can also contribute to damp problems.
- Porous Building Materials
Bricks, mortar, and plaster naturally absorb moisture, meaning that if a DPC is missing or ineffective, water will continue to rise through the structure. Some modern renovations, such as cement-based plaster, can trap moisture rather than allowing it to evaporate, making the problem worse.
How to Prevent Further Damage
Since multiple factors can contribute to rising damp, an accurate diagnosis is key. Simply replacing plaster or painting over damp patches won’t fix the problem. A full damp survey from Home Energy Save GB will identify the root cause, ensuring that the right solution is applied to prevent further damage and to determine the exact cause.
How to Diagnose Rising Damp
Correctly diagnosing rising damp is essential to ensure the right treatment. Many homeowners waste money on unnecessary repairs because damp issues are frequently misidentified. Rising damp can be confused with condensation or penetrating damp, making a professional assessment crucial.
Key Steps in Diagnosis
- Visual Inspection
Rising damp typically appears as damp patches, tide marks, and salt deposits up to one metre high on walls. Unlike condensation, which forms on cold surfaces, or penetrating damp, which results from leaks, rising damp always originates from ground level.
- Moisture Meter Testing
A moisture meter is used to check damp levels inside walls. If moisture readings are highest at the base and gradually decrease upwards, this pattern indicates rising damp rather than another type of damp issue.
- Salt Testing
Rising damp carries ground salts, which are left behind as moisture evaporates. These salts are hygroscopic, meaning they attract moisture from the air, keeping walls damp. Testing for nitrates and chlorides confirms if the damp originates from the ground, ruling out condensation or internal leaks.
- Specialist Surveys
Damp isn’t always visible to the naked eye, and surface tests alone may not reveal the full extent of the problem. Home Energy Save GB (HES) offers comprehensive surveys using advanced digital instruments, allowing for accurate detection of moisture levels deep within walls. This ensures the correct diagnosis and prevents costly, ineffective treatments.
Many damp-proofing companies only recommend solutions based on their product range. We provide a full survey covering all potential causes—including chimney leaks, structural issues, and external drainage—ensuring you get the right solution, not just a quick fix.
If you suspect rising damp, getting a professional survey early can save thousands in unnecessary repairs.
Impacts of Rising Damp
If left untreated, rising damp can cause significant structural damage, increase heating costs, and create serious health risks. The longer the issue persists, the more expensive and disruptive the repairs become.
Structural Damage & Property Value
- Weakened walls – Moisture breaks down brickwork, mortar, and plaster, leading to crumbling and decay.
- Rotting woodwork – Skirting boards, flooring, and door frames can warp, crack, or rot, requiring costly replacements.
- Stained & damaged interiors – Peeling wallpaper, blistering paint, and visible damp patches make a home look neglected and harder to sell.
- Lower property value – Rising damp is a red flag for buyers. Mortgage lenders often require damp issues to be resolved before approving loans.
Higher Energy Costs
- Damp walls lose heat faster – Moisture reduces insulation efficiency, making homes colder and more expensive to heat.
- Increased heating bills – Homeowners often overuse heating to compensate for the heat loss caused by damp walls.
Health Risks
- Mould growth – Damp conditions encourage mould spores, which can trigger respiratory issues, allergies, and asthma.
- Poor indoor air quality – A musty smell and increased humidity can make a home feel uncomfortable and unhealthy.
- Higher risk for vulnerable people – Children, the elderly, and those with asthma are particularly affected by damp-related health problems.
How to Avoid These Problems
Early detection prevents costly structural repairs and health issues. The only way to accurately assess the impact of rising damp is through a professional damp survey. Home Energy Save GB provides comprehensive assessments, ensuring that homeowners get the right treatment before the problem worsens.
How to Treat Rising Damp
Treating rising damp effectively requires addressing the root cause, not just covering up the symptoms. The right solution depends on the severity of the problem, the condition of the DPC, and the materials used in the property.
1. Install or Repair a Damp Proof Course
A DPC prevents moisture from rising through walls. If the existing barrier is damaged or missing, it must be repaired or replaced.
- For modern homes – If the DPC is failing, a cream injection DPC can reinforce the barrier. Unlike traditional chemical injections, cream DPCs are more effective, longer-lasting, and easier to apply.
- For older homes – If no DPC exists, a cream DPC can be installed. A physical DPC (such as a new plastic or slate membrane) is also possible but is more expensive, time-consuming, and disruptive.
2. Lower External Ground Levels
If soil, paving, or driveways are above the DPC, moisture can bridge the barrier, rendering it ineffective.
- Ensure external ground levels are at least 150mm (6 inches) below the DPC to prevent water from bypassing it.
- If necessary, remove excess soil or adjust landscaping to improve drainage.
3. Improve Drainage Around the Property
Poor drainage can cause water to accumulate near the foundations, increasing the risk of rising damp.
- Ensure gutters and downpipes are clear and directing water away from the house.
- Repair leaking pipes or drainage systems that could be contributing to damp problems.
4. Strip & Treat Affected Walls
Once the rising damp is under control, any damaged plaster must be removed and replaced.
- First, apply a salt-retardant treatment – Since rising damp carries hygroscopic salts (which attract moisture from the air), a salt-retardant layer is needed to prevent future issues.
- Next, apply a waterproof membrane – This may be plastic, cement-based, or a tanking slurry, depending on the thickness of the plaster and the wall type.
- Finally, replaster the area – The new surface should be breathable and moisture-resistant to prevent damp returning.
5. Ventilate to Assist Drying & Prevent Mould
Once treated, walls can take up to 12 months to fully dry out.
- Keep rooms well-ventilated – This prevents mould growth while the wall is drying.
- Avoid non-breathable paints or wall coverings – These trap moisture and can lead to further problems.
6. Get a Professional Damp Survey for Any Signs of Damp
If damp isn’t always visible, homeowners may not realise the extent of the problem. A specialist survey from Home Energy Save GB ensures that the right treatment is applied before further damage occurs.
We use advanced digital instruments to detect moisture deep within walls – identifying damp before it becomes a costly issue. Booking a survey early can prevent unnecessary repairs and long-term damage.
Preventing Rising Damp
Preventing rising damp is often misunderstood because many homeowners assume they can maintain or check their damp proof course themselves. However, in reality, a DPC is embedded within the structure of a building, making it impossible to assess without specialist equipment. Many older homes were built with slate or bitumen-based damp courses, which can degrade over time due to environmental factors, structural movement, and increased ground vibrations from modern traffic.
One of the most effective ways to reduce the risk of rising damp is by managing external ground levels. If soil, paving, or other structures are positioned too high against an external wall, moisture can bypass the DPC entirely, leading to rising damp. Ensuring the ground level remains at least 150mm below the damp course helps maintain its effectiveness.
Drainage also plays a crucial role in preventing moisture build-up around a property. Blocked or poorly maintained gutters and downpipes allow water to accumulate near the foundations, increasing the likelihood of damp issues. Regular maintenance of these systems can prevent excess moisture from reaching the walls in the first place.
While ventilation is often associated with condensation, it also has a role in damp prevention. If a wall has absorbed moisture, good airflow can aid the drying process and help prevent mould growth. Rooms affected by damp should be kept well-ventilated, particularly during and after treatment.
Although these steps can help limit moisture exposure, they don’t eliminate the risk of rising damp entirely. Many factors, including structural weaknesses, historic building materials, and previous incorrect treatments, can contribute to the issue. The only way to accurately determine a property’s vulnerability to rising damp is through a professional damp survey.
Home Energy Save GB conducts comprehensive, inductive damp detection surveys, assessing moisture levels deep within walls—far beyond what a surface check can reveal. Without this level of investigation, homeowners may not realise they have an issue until visible damage appears. Catching the problem early can save thousands in unnecessary repairs and ensure that the correct solutions are applied before damp becomes a more serious concern.
Overall, just remember that rising damp isn’t just an inconvenience—it’s a serious issue that can weaken your home’s structure, increase heating costs, and create long-term health risks. The biggest mistake homeowners make is delaying action or relying on quick fixes that don’t address the root cause.
The only way to properly deal with rising damp is through a full professional diagnosis. Without it, you could end up wasting money on ineffective treatments or covering up symptoms while the problem worsens behind the scenes.
Home Energy Save GB (HES) provides comprehensive damp surveys that go beyond surface-level inspections. Using advanced digital detection, HES ensures the correct diagnosis from the start, so you avoid unnecessary repairs and costly mistakes.
If you’ve spotted any signs of damp, don’t wait—book a professional damp survey today and protect your home before the damage gets worse.