Published on 19/03/25 & updated on 23/04/25

Rising damp is a common problem in UK buildings and properties. Currently, 15 million or 28% of the UK population reports living in homes with problems related to damp and mould.

Research also shows the average UK homeowner spends over £15,000 on home improvements. This is particularly true when it comes to older properties built before modern damp proofing methods were adopted, such as physical Damp Proof Courses (DPCs). Many homeowners don’t realise what causes rising damp in buildings, especially in properties built before modern damp-proofing systems.

So, What Is Rising Damp in Buildings?

In short, rising damp is moisture penetration that occurs when groundwater travels through porous building materials, such as bricks, concrete blocks, and some stones. Rising damp occurs when groundwater rises through walls due to capillary action. Understanding what causes rising damp in buildings helps homeowners identify the signs early.

In most cases, mould and damp can rise to around one metre, although under severe conditions, it may travel higher depending on the wall’s porosity

This occurs due to capillary action, a phenomenon whereby liquids can travel horizontally or vertically in small spaces within materials. 

Other porous materials, such as plasterwork and the timber found in floorboards and skirtings, can also absorb the groundwater, which can result in rot and an array of other issues over time.

What Problems Can Rising Damp Cause?

Rising damp can cause an array of problems, including:

• Damp Patches: Damp patches commonly appear at the base of the wall.
• Salt Deposits: Efflorescence is the process by which salt migrates to the surface of a porous material. It’s often found on the surfaces of walls when rising damp is present.
• Peeling Paint or Wallpaper: This is due to higher water levels in your wall, loosening the paint or wallpaper.
• Deterioration of Plaster & Brickwork: When there are high levels of moisture in your walls, this can result in crumbling and flaking plaster and brickwork.

Knowing what causes rising damp in buildings also helps you recognise these symptoms early, before they affect structural materials.

Porous materials, such as plasterwork and the timber found in floorboards and skirtings, can absorb the groundwater and result in an array of issues.

Can Rising Damp Cause Health Issues?

Yes, rising damp can cause health issues. This doesn’t happen directly, but the conditions it creates can have a negative impact on your health.

Excess moisture in walls can increase humidity and cause mould growth, which may trigger respiratory problems, allergies, and worsen conditions such as asthma. Damp environments can also contribute to dust mites and overall poor indoor air quality, especially if your home is poorly ventilated.

This is why it’s crucial to address rising damp as soon as you notice it.

Damp Proof Courses In UK Construction

As mandated by the Building Regulations, damp proof courses are now a requirement when constructing new buildings to prevent rising damp and, in some cases, penetrating damp.

These regulations apply to new constructions and existing buildings undergoing certain modifications, such as renovations and extensions.

Damp proof courses are now a requirement when constructing new buildings to prevent rising and penetrating damp.

Today, modern buildings include physical DPCs, which are made from plastic or polythene membranes, bitumen or asphalt layers, or non-porous engineering bricks.

The choice of DPC material depends on a range of factors, from the age of the property to budget considerations.

That said, these physical barriers are built into the base of the wall to help ensure long-term protection against rising damp.

How Damp Proof Course Prevents Rising Damp

A Damp Proof Course acts as a protective barrier when installed in walls to prevent moisture within a building from rising above a certain level.

A Damp Proof Course works in the following ways:

• Physical Barrier: A physical DPC is a protective, horizontal barrier that is installed close to the bottom of the property’s walls to stop rising damp.
• Chemical Treatment: Modern solutions involve injecting chemicals into walls to create a water-repellent layer that prevents water from rising.
• Integral Waterproofing: Some newer builds are constructed with water-resistant materials to prevent moisture absorption.

Without an effective Damp Proof Course, buildings are more susceptible to rising damp.

This can lead to an array of problems, from damaging structural timbers that can threaten further damage to your property to unhealthy living conditions.

Proper maintenance and repairs carried out by damp proofing specialists are essential to prevent damp in the long term. Without a functioning DPC, mould and damp can rise surprisingly high up a building, especially if the wall is highly porous.

If you’ve noticed signs of mould or damp in your property or want to take preventative action, get in touch with our rising damp specialists at Protectahome today to book a survey of your home.

Can Old Houses Be Damp Proofed?

Yes, old houses and buildings can be damp-proofed.

In the UK, houses are considered to be ‘old’ when they predate 1940. One of the most common questions homeowners ask is how to stop rising damp in old buildings, especially those without an original Damp Proof Course.

Old houses and buildings can be damp-proofed. To find out what options are available to you, contact Protectahome today.

Many Victorian and Edwardian homes, for example, were built without a physical Damp Proof Course.

Instead, these houses relied on breathable materials and thick masonry walls to help regulate the moisture levels within buildings, leaving owners of older properties without the benefits of a Damp Proof Course.

In some circumstances, a DPC might have failed over time due to earlier methods, such as slate or bitumen, that have degraded or been bridged by renovations over the course of the years.

The good news is that modern damp-proofing solutions can be carefully adapted for older properties.

How Do You Stop Rising Damp?

Here are some damp proofing options you can use to treat damp in your property:

1. Chemical DPC Injections

This is a cost-effective damp proofing solution that involves injecting a water-repellent chemical into the wall to treat rising damp.

2. Internal Membrane Lining System 

This involves lining the internal faces of the walls with an HDPE (High Density Polyethene) Membrane, often with a meshed surface allowing for direct application of plaster, render or dot & dab plasterboard. 

3. Physical DPC Retrofitting 

This is when a physical layer of plastic or lead sheeting is inserted into the base of the walls.

In summary, many older homes in the UK lack a DPC or have an outdated system, making them more susceptible to rising damp.

How We Can Help with Rising Damp in Buildings

If you have a rising damp problem and are looking for a damp proofing solution, Protectahome can help.

Our damp proofing specialists have over 45 years of trading and experience behind them and have a wealth of experience in damp proofing basements, cellars, and walls in an array of homes and buildings.

If you’re unsure what causes rising damp in buildings or how to treat it, our specialists can diagnose the issue and recommend the right repair method. Contact us at 0800 055 6966 or web@protectahome.co.uk to arrange a survey of your home.