Professional Damp Investigation & Damp Proofing
Damp can be frustrating – particularly when you’ve already tried to deal with it, and the staining, mould or damaged plaster simply returns. At KJ Roofing & Building, we provide professional damp investigation, damp proofing and associated building repairs throughout Wrexham, North Wales, Flintshire, Cheshire and the surrounding areas.
Our approach is simple: identify the true cause of the damp, before recommending a solution.
Not every damp patch is rising damp. Not every damp chimney breast is caused by a roof leak. In some cases, condensation, salts within the plaster or historic moisture are what’s really responsible for recurring damp-looking patches. Getting that distinction right matters – treating the wrong cause means unnecessary work and expense, while the original problem remains.
Identifying Different Types of Damp
Damp can enter or develop within a property for many different reasons, and several types of damp can produce similar symptoms. During an assessment, we consider the location, pattern and condition of the affected area, together with the condition of the surrounding building, and look at potential causes including:
The aim is to establish the most likely source of the moisture before deciding what work, if any, is required.
A Common Misdiagnosis
Chimney Damp Isn’t Always a Roof Leak
Damp appearing around a chimney breast is often assumed to be caused by a leaking roof or chimney stack. While damaged flashing, defective pointing, cracked masonry and other external defects can certainly allow rainwater in, a roof leak isn’t always the cause. Chimney breasts can be affected by a combination of factors, including rainwater penetration, condensation, cold chimney masonry, poor ventilation, historic use of fireplaces, moisture trapped within old masonry, hygroscopic salts, previous chimney alterations and defective flashing or leadwork. This is why chimney damp can sometimes be particularly difficult to diagnose.
Hygroscopic Salts
One of the less obvious causes of recurring staining on an old chimney breast is hygroscopic salt contamination. Over many years, fireplaces burning coal, wood or other fuels can leave deposits within the chimney and surrounding masonry. Moisture entering the chimney – historically through rainwater penetration, or through condensation within the flue – can dissolve and move these salts through the porous masonry and plaster. Some of these salts are hygroscopic, meaning they can attract and hold moisture from the surrounding air.
Why Does It Keep Coming Back?
A chimney breast can appear dry for periods and then develop staining, bubbling paint or damp-looking patches again when humidity in the room increases – from cooking, drying clothes indoors, showering, poor ventilation or colder weather. Hygroscopic salts within contaminated plaster can absorb this atmospheric moisture, resulting in recurring staining even though the original water source may have already been repaired. This can give the impression there’s still a roof leak, when the problem is actually the salts within the plaster and the internal environment.
Salt-Contaminated Plaster
Salt deposits can appear as white, powdery or crystalline marks on walls and chimney breasts, or present as bubbling or flaking paint, staining, crumbling plaster, wallpaper lifting away, or a surface that appears damp despite no obvious active leak. Simply painting over the affected area may only provide a temporary cosmetic improvement – if salts remain within contaminated plaster, they can continue to affect the new decoration.
This is why the condition of the existing plaster needs to be considered alongside the possible source of moisture – not just where the staining happens to be showing.
Rising Damp
Rising damp occurs when moisture from the ground moves upwards through porous building materials. It can sometimes present as:
However, these symptoms are not exclusive to rising damp. Other problems, including plumbing leaks, penetrating damp and condensation, can produce similar signs – which is why we never assume a damp patch automatically means a new damp-proof course is required.
Penetrating Damp
Penetrating damp occurs when moisture enters the property from outside. There are many potential causes:
Penetrating damp often becomes more noticeable following periods of heavy or persistent rainfall. Finding and repairing the external source of the moisture is an essential part of resolving the problem for good.
Condensation Can Look Like Damp
Not every damp-looking wall is suffering from water entering the building. Condensation – warm, moist air meeting a colder surface such as an external wall or an old chimney breast – is one of the most common causes of moisture problems inside properties. Chimney breasts are particularly susceptible, since old masonry stays cold once a fireplace is no longer in regular use.
Signs it may be contributing to the problem include:
Where condensation is the underlying cause, installing damp-proofing alone won’t solve the problem – ventilation, heating, airflow and moisture levels within the property need to be considered too.
Why Correct Damp Identification Matters
There is no single treatment that is suitable for every damp problem. For example:
This is why we believe in investigating the cause before recommending the treatment. Our aim is to provide honest, practical advice and avoid recommending unnecessary work.
Damp Proofing & Remedial Building Work
Depending on what is found during the assessment, suitable remedial work may include:
Where plaster has become damaged through prolonged moisture or salt contamination, we can advise on the most appropriate approach to restoring the affected area. The correct method depends on the cause of the damp, the condition of the existing materials and the construction of the property.
Local & Trusted Damp Proofing Services
KJ Roofing & Building is a local, professional roofing and building company based in Wrexham, serving customers throughout Wrexham, North Wales, Flintshire, Cheshire and surrounding areas. We understand that having work carried out on your home requires trust – that’s why we explain what we’re seeing and discuss the options available before any work is undertaken.
Frequently Asked Questions
Do I definitely need a new damp-proof course if I have a damp patch?
Not necessarily. Symptoms like damp patches, damaged plaster or salt deposits can also be caused by plumbing leaks, penetrating damp or condensation. We assess the property first to establish the most likely cause, rather than assuming a new damp-proof course is needed.
Why does damp keep coming back on my chimney breast, even after a leak was repaired?
This is often down to hygroscopic salts left behind in the plaster from historic moisture or old fireplace use. These salts can absorb moisture from the air in the room, causing staining to reappear even though the original source of water has already been fixed.
Is condensation the same as damp?
Not exactly. Condensation happens when warm, moist air meets a colder surface, rather than water entering the building from outside or the ground. It can produce very similar symptoms to damp, such as mould and staining, but the underlying cause and the fix are different.
How do you work out what’s actually causing the damp?
We look at the location, pattern and condition of the affected area alongside the wider condition of the building – things like the roof, flashing, guttering, pointing, plumbing and ventilation – to establish the most likely cause before recommending any work.
Do you carry out the repair work as well as the damp investigation?
Yes. Depending on what the assessment finds, we can carry out the appropriate remedial work ourselves, from roof, flashing and brickwork repairs to remedial plastering – so you’re not left having to find a separate contractor for the fix.
Concerned About Damp in Your Property?
Whether you’re dealing with suspected rising damp, penetrating damp, condensation, chimney damp, salt staining or an unexplained damp patch, we’re here to help. Contact KJ Roofing & Building today to discuss your damp problem.
KJ Roofing & Building — Local. Professional. Reliable.