Damp issue in an old house

How to Treat Rising Damp in an Old House?

Key Takeaways

Causes of Rising Damp in Old Houses: Absent or defective damp-proof course (DPC) is a common factor in older homes. Porous materials like stone, brick, and lime mortar contribute to vulnerability. Elevated ground levels and defective drainage intensify the risk of rising damp. Signs of Rising Damp: Damp patches at the base of walls. Tidelines from salt deposits. Peeling paint, cracked plaster, and a musty odour. Damaged woodwork near damp walls. Impact of Rising Damp: Mould in damp environments can lead to respiratory issues and allergies. Moisture intrusion can damage foundations, walls, and structural components. Damp-infested homes may have reduced market value, impacting potential buyers.   Old houses are more prone to getting rising damp. The primary reason behind this is the eradication of the damp-proof course situated at the foundation of the house. As time passes, this damp-proof course starts eroding and ultimately fails to provide any protection against rising damp treatment. Therefore, rising damp starts to creep through the walls – destroying the plaster, paintwork, and other structural parts. In worse conditions, rising damp travels all the way up to the ceilings and weakens the roof structure, which can be dangerous if someone is living in the house. Given rising damp can pose some serious threat to both the house and the people living in it, it must be fixed at any cost. But what if the house is old? Can it still be fixed? Well, it can be. It might take some effort, but it can be fixed. Let's see how. Complete destruction of a store room due to dampness  

What is it that Causes Rising Damp in an Old House?

Old houses, with their beauty and character, also show up unexpected issues. Rising damp is often a quiet intruder that creeps up from the earth, leaving moist spots, flaking paint, and a musty stench in its wake. But what precisely is rising damp, and why are older homes more vulnerable?

Rising Damp

Rising damp happens when groundwater from the soil migrates upwards through a building's walls. For a more precise understanding, imagine millions of tiny capillaries - microscopic tubes inside the stonework - working as straws, sucking moisture up through a natural process known as capillary action. This moisture then evaporates within the walls, leaving salts and minerals that corrode plaster, paint, and even the structural integrity of your house.

Why are Older Houses Susceptible to Rising Damp?

Several factors converge to render older houses particularly susceptible to the insidious threat of rising damp:

Absent or Defective Damp-Proof Course (DPC)

In stark contrast to their modern counterparts, which boast an effective barrier against groundwater intrusion, many older houses constructed prior to the 20th century either lack a DPC altogether or suffer from the deterioration of their existing damp-proof courses. These crucial elements, typically composed of waterproof materials such as plastic sheeting or chemical injections, play a pivotal role in halting the infiltration of moisture into the walls. Unfortunately, the passage of time often erodes the efficacy of these barriers, leaving the structure vulnerable to the creeping menace of rising damp.

Porous Materials

The very materials that lend charm and character to older homes, such as stone, brick, and lime mortar, inadvertently contribute to their vulnerability. Unlike the more impermeable materials utilized in contemporary construction, these traditional building components exhibit higher levels of porosity. This inherent permeability facilitates the unhindered penetration of moisture, allowing rising damp to take root and ascend through the fabric of the walls, manifesting as damp patches and compromising the structural integrity of the edifice.

External Ground Levels

The topography surrounding older houses becomes a critical factor in the battle against rising damp. Elevated ground levels encircling the dwelling exert additional pressure on the DPC, intensifying the likelihood of water ingress. As the external, ground level rises, it amplifies the force with which groundwater presses against the walls, undermining the DPC's ability to repel this insidious moisture. Consequently, the elevation of external ground levels emerges as a compounding factor that exacerbates the risk and extent of rising damp in these aged structures.

Defective Drainage

The efficacy of drainage systems in the vicinity of an older house is instrumental in safeguarding it against the encroachment of rising damp. Blocked or damaged drains, if left unattended, transform into reservoirs of water that readily find their way into the building's walls. This unchecked influx of water serves as a constant source, perpetuating the conditions conducive to rising damp. Thus, maintaining a functional and unobstructed drainage network is paramount in mitigating the risks posed by rising damp in older residences. Damaged wall due to excess moisture content  

What are the Signs of Rising Damp?

Early detection is critical to combating rising damp effectively. The following signs are what can indicate the presence of rising damp in the house:

Damp Patches

Keep a watchful eye for the emergence of damp patches, typically observable at the base of walls. These patches often extend vertically, covering a meter or more. Identifying and addressing these areas promptly can prevent further escalation of the rising damp issue.

Tidelines

Be mindful of visible tidelines that materialize as a consequence of moisture evaporation. Salt deposits left behind on the wall surface create discernible lines, serving as an unmistakable sign of the presence of rising damp.

Peeling Paint and Cracked Plaster

The insidious nature of rising damp weakens the adhesive bond between paint and plaster. Consequently, vigilant homeowners should be on the lookout for signs of peeling paint and cracked plaster. These visual cues not only compromise the aesthetic appeal of the property but also serve as precise indications of underlying moisture-related issues.

Musty Odour

A distinctive musty smell should not be ignored, as it can be a red flag signalling the presence of mould and mildew. These fungi thrive in damp environments and can pose health risks to occupants.

Damaged Woodwork

Pay special attention to the condition of woodwork, such as floorboards and skirting boards, in close proximity to damp walls. Moisture infiltration can cause wood to rot and warp, leading to structural instability. Dampness and wetness penetrating through walls and ceiling  

How to Treat Rising Damp in an Old House?

Conducting a Survey

Begin the resolution procedure by thoroughly determining the source and degree of the damp problem. Conducting a comprehensive inspection is critical to developing an appropriate solution adapted to the scenario. This thorough analysis not only helps to pinpoint the core cause of the damp but also provides a complete understanding of the elements that contribute to its persistence. This investigation technique allows you to learn about the exact regions impacted, potential structural concerns, and environmental variables impacting damp. Whether the problem is caused by leaks, condensation, or other factors, a thorough inspection ensures that no underlying issues are neglected, allowing for a more effective and long-lasting remedy.

Repairing Defective Roofing

A damaged or leaky roof can pose significant risks to the integrity of your home, potentially leading to damp and other structural issues. To fortify your property against these concerns, it is crucial to undertake timely and effective repairs on any defective roofing components. One of the primary culprits in compromising the structural soundness of a dwelling is a leaky roof. Therefore, it becomes imperative to conduct regular inspections and address any signs of wear and tear promptly. The first line of defence against water ingress is to ensure that your roof is in optimal condition. Act swiftly to identify and rectify any damaged or missing tiles, as they can serve as entry points for water during rain or snowfall.

Repointing Brickwork

As time wears on structures, the mortar seams that hold bricks together can deteriorate. This slow wear and tear not only degrades the structure's visual appeal but also allows for potential water penetration. This is where repointing emerges as a critical intervention to strengthen the resistance and durability of brickwork. Repointing is the methodical repair of mortar joints by intentionally replacing old and damaged material with a precisely designed mortar mix. This technique is more than just a cosmetic undertaking; it is a necessary step in protecting a building's structural integrity. Repointing serves as a buffer, keeping water from seeping into the walls and creating gradual harm under the surface. The selection of a suitable mortar mix is an integral part of the repointing process. Compatibility with existing brickwork, climatic concerns, and historical accuracy are all critical components in this decision-making process. The use of the appropriate materials provides a smooth integration of the new mortar with the old, resulting in a cohesive and lasting bond that can endure the test of time and weather. Dampness on ceiling which caused brick exposure

Applying Waterproof Sealants

When thinking about improving moisture resistance for external and internal walls together, it is strongly advised to use specialist waterproof sealants. These sealants act as a robust line of defence, adding an extra layer of protection to effectively reduce the hazards connected with moisture infiltration. Applying these modern sealants not only strengthens the structural integrity of your external walls but also protects the internal rooms from water damage. The installation of waterproof sealants is a careful operation in which the chosen sealer is carefully distributed across the surface of the exterior walls. This forms a strong barrier that protects the structure from rain, humidity, and other environmental conditions that might compromise its structural integrity. The sealants provide a durable layer that prevents water from penetrating the walls, preventing mould growth, damage, and building material deterioration.

Utilizing Dehumidifiers

Dehumidifiers are an effective and intelligent way to manage moisture levels in wet settings. A variety of advantages can be gained by introducing these devices into locations prone to excessive humidity. Dehumidifiers perform an essential function in controlling ambient moisture, reducing the danger of damp and preventing mould growth. Dehumidifiers are essential in areas with high humidity, such as basements, restrooms, and kitchens. These devices work by removing excess moisture from the air, making the environment less favourable to the growth of mould and mildew. By doing so, they not only improve the general comfort of the living or working environment but also help to maintain structure integrity and indoor air quality. Furthermore, the use of dehumidifiers goes beyond simple avoidance, as they work as a proactive precaution against potential health risks linked with moist air and surroundings. Mould spores, which flourish in high-humidity environments, can cause respiratory problems and worsen allergies. Dehumidifiers, by managing humidity levels, protect against these health risks, producing a healthier and more livable environment. Fluffy plasterwork due to dampness

Addressing Interior Damage

When dealing with damp-related interior damage, complete repairs are required to restore the afflicted surfaces and exceptionally deteriorated materials such as plaster or paint. Begin by determining the amount of the damage, including whether it affects only a few locations or necessitates more comprehensive repair operations. Start the restoration procedure by removing any vulnerable components, such as water-damaged plaster or paint, to reveal the underlying structure. Thoroughly dry the afflicted areas to prevent moisture from causing additional degradation and the formation of mould or mildew. After the damaged portions have dried, proceed with the necessary repairs. This might include mending or reapplying plaster, repriming surfaces, or repainting damaged sections. Ensure that the repairs are not merely cosmetic but also address any structural difficulties that may have developed as a result of extended exposure to wet conditions. When planning future renovations, it is best to emphasize the usage of moisture-resistant materials. Choose construction materials and finishes that can endure damp, lowering the chance of future damage. Consider moisture-resistant paints, water-resistant drywall, and other appropriate solutions to help protect your interior from the negative impacts of damp.

Replacing the Damp-proof Course

A defective or nonexistent damp-proof course is a common source of growing damp in buildings, particularly in older homes. When dealing with damp wall-proofing issues, the most typical solution is to have a damp professional apply a damp-proofing cream to the wall, thereby renewing the course. This unique cream is precisely injected into the brickwork via strategically positioned drill holes. Once the cream has cured, it produces a protective barrier that prevents moisture from moving upward through the brickwork. This ingenious method provides a robust defence against the negative consequences of growing damp. An alternate option requires installing an entirely new damp-proof course, which is a more invasive process. This method involves the removal of up to two courses of bricks to allow for the installation of the new protective layer. While more intrusive, this technology offers a thorough and long-term solution to concerns connected with a damaged damp-proof course, assuring improved moisture control throughout the building. Peeling of plaster work due to dampness

Using Damp-proof Paint

Aged constructions are vulnerable to penetrating wet due to increasing porosity in their brickwork, which allows moisture penetration. A feasible solution to this problem is to use damp-proof paint, which is silicone-based and has water-repellent characteristics. This particular coating acts as a protective barrier against solid walls, preventing moisture from entering the structure. Damp-proof paint, which is silicone-based, serves as an effective barrier against the adverse effects of water infiltration. Its water-resistant characteristic not only protects the property's structural integrity but also contributes to a healthier indoor atmosphere by inhibiting the formation of mould and mildew. Nonetheless, the effectiveness of damp-proof paint is dependent on picking the suitable solution for the exact age and condition of the home in question. Seek professional help to achieve the best possible outcomes and long-lasting protection. Professionals have the experience to examine the intricacies of your property's specific characteristics and make personalized advice on the best damp-proof paint for successful moisture-related protection.

Install Air Bricks

Ensuring sufficient air circulation under the flooring of older houses, particularly those without hollow walls and with timber ground floors, is critical in preventing damp-induced rot. To successfully solve this issue, air bricks installed below the floor level are highly suggested. By substituting conventional bricks with air bricks, you may enhance ventilation and reduce the danger of moisture collection and decay. These specifically shaped bricks allow for the flow of air, which helps to maintain ideal conditions beneath the floor and protects against the adverse effects of wetness. In addition to putting air bricks, consider placing vents around chimney stacks. These vents have an essential function in increasing air circulation and lowering the possibility of damp development. Deliberately implementing these ventilation methods may help you construct a comprehensive system that fosters a dry and well-ventilated environment beneath the property, thus increasing the building's lifetime and structural integrity. Rising damp on a wall affected by moisture  

What Impact Does Rising Damp Leaves?

The presence of rising damp extends beyond mere aesthetic worries, encompassing profound implications for both health and economic well-being:

Health Implications

The presence of moisture in living spaces and the subsequent proliferation of mould can serve as significant triggers for a myriad of health issues. Those inhabiting damp environments often find themselves grappling with respiratory challenges, heightened allergic reactions, and an array of other health complications. This underscores the crucial imperative for proactive measures in the prevention and effective management of damp within living spaces. Implementing strategies to control and mitigate damp conditions is essential to safeguarding the well-being of individuals and promoting a healthier living environment.

Structural Deterioration

Neglecting the issue of growing damp poses a considerable risk to the overall structural stability of a home. Moisture intrusion over time may cause significant damage to a building's foundation, walls, and other structural components. This cumulative damage might eventually need extensive and costly repairs, emphasizing the crucial significance of responding quickly and efficiently to developing damp problems. Prompt intervention is required to reduce the danger of structural damage and the cost load associated with significant repair activities.

Diminished Property Value

The repercussions of living in a damp environment extend to the financial realm, impacting the overall value of a property. Potential buyers are likely to be deterred by the prospect of a damp-infested residence, translating into a diminished property value. Addressing rising damp not only safeguards the structural integrity of a home but also preserves and potentially enhances its market value, underscoring the dual importance of proactive damp management for homeowners and property investors alike. Rising damp on the corner of two walls  

The Bottom Line

The prevalence of rising damp in old houses is a consequence of the gradual deterioration of the foundational damp-proof course over time. This erosion leaves the structure vulnerable to the infiltration of damp, leading to the degradation of plaster, paintwork, and even critical structural elements. In more severe cases, the upward progression of rising damp can extend to ceilings, compromising the integrity of the roof and posing potential hazards for occupants. Recognizing the imminent threat it poses to both the dwelling and its inhabitants, addressing rising damp becomes imperative. Despite the challenges presented by the age of the house, remediation is not only feasible but essential. Although rectifying the issue demands a concerted effort, the prospect of restoring the damp-proofing mechanisms underscores the significance of safeguarding the historical and structural integrity of ageing residences.  

Is rising damp common in old houses?

Rising damp is a common issue in many old buildings and houses, especially those with porous masonry or inadequate damp-proofing measures. It occurs when moisture from the ground travels up through walls, leading to visible damp patches, peeling paint, and potential structural damage. While prevalent, rising damp can often be addressed through professional interventions.

Can you treat rising damp yourself?

Treating rising damp yourself is generally not recommended, as it requires specialized knowledge and equipment. Effective damp treatment often involves identifying the source of damp, repairing or installing damp-proof courses, and addressing any structural issues. DIY attempts may not provide a lasting solution and could result in further damage or financial costs in the long run.

Can you put a damp proof course in an old house?

Installing a damp-proof course (DPC) in an old house is feasible but should ideally be carried out by professionals. A DPC is a barrier inserted into the walls to prevent moisture from rising from the the exterior ground level. The process involves drilling into the walls and injecting a waterproofing solution. Retrofitting a DPC in an old house requires careful assessment to determine the most suitable method, and professional assistance ensures proper installation and effectiveness.

Is treating rising damp expensive?

The cost of treating or fixing rising damp can vary depending on factors such as the severity of the issue, the size of the affected area, and the chosen treatment method. Professional assessments are crucial for accurate cost estimates. While treating rising damp may involve a significant investment, addressing the issue promptly can prevent further damage and potential health hazards, making it a worthwhile investment in the long-term maintenance of a property.

Table of Contents

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

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