Penetrating damp is the process of moisture seeping from the exterior wall of a building to the interior. It occurs when outside moisture like wind-driven rain impacts a building’s wall. Building materials like brick and render are porous. They soak up rain to saturate the wall with penetrating damp.
Rain penetration into masonry can occur in buildings of all ages. Properties with large exposed walls are often far more vulnerable to penetrating damp, especially during prolonged periods of wind driven rain. End terraces, semi-detached homes and detached properties commonly suffer the worst because their gable end walls take the full force of the weather year after year.
High level walls are also particularly prone to water penetration due to constant exposure to rainfall, failed pointing, cracked render and deteriorated masonry. At its most obvious, it penetrates the wall and displays as a damp patch on the internal wall. This causes discolouration, paint and wallpaper peeling and flaking and at its worst plaster becoming loose/falling off.
Wind driven rain in masonry can cause what seem like never ending problems, even if you cannot visibly see it penetrating through the entirely of a wall, over time it will appear.
Without external protection, masonry continues absorbing rainwater year after year, leading to internal damp, heat loss, moss growth, render/mortar damage, frost damage and structural deterioration.
Resulting in causing a damp environment which will cause spores in the air to settle. Mould and mildew begin to grow, which can be very harmful to a human.
What is penetrating damp?
What is rising damp?
Rising damp occurs when groundwater rises through capillaries in masonry to saturate it. To prevent this, modern homes are built with a DPC (Damp-Proof Course) which acts as a water repellent barrier to stop moisture rising up your walls.
There are several ways rising damp occurs, in older buildings, it is often caused by a faulty or missing DPC. In newer buildings, rising damp is often caused by adjoining structures that introduce moisture above the DPC.
At Yorkshire Damp & Waterproofing Ltd, we only provide the most up to date, tested and proven Damp Proofing technology. Using active ingredients that will create a waterproof barrier lasting 20+ years.
Please check out our services page for more information on Damp Proof Solutions.
Common Damp Proofing Myths
Myth 1 - “ Damp will dry out on its own”
Damp problems rarely disappear without treatment. In most cases, moisture continues entering the property through failed masonry, damaged pointing, cracked render or defective damp proofing. Left untreated, the problem often becomes worse over time and can eventually lead to internal damage, mould growth and costly repairs.
Myth 2 - “Painting over damp will solve the problem”
Simply painting over damp patches or mould only hides the symptoms temporarily. Unless the source of moisture is identified and treated correctly, the damp will usually return. Proper preparation and external protection are essential for long-term results.
Myth 3 - “Waterproof coatings stop walls from breathing”
Modern breathable masonry protection systems are specifically designed to repel external rainwater while still allowing trapped moisture vapour to escape from the wall. This helps protect the property without sealing moisture inside the masonry.
Myth 4 - “New houses can’t suffer from damp”
Both old and modern properties can experience damp problems. Poor workmanship, cracked render, inadequate ventilation, cavity wall issues and external weather exposure can affect homes of any age. We have sealed many new homes, which will keep them damp free and looking new for many years to come!
Myth 5 - “Damp is only a cosmetic issue”
Damp can lead to much more than stained walls and peeling paint. Ongoing moisture problems can contribute to mould growth, timber decay, damaged plaster, heat loss and deterioration of external masonry if ignored for long periods.
Myth 6 - “Internal damp proofing alone fixes the issue”
Treating the inside of a property without addressing the external source of water ingress often means the problem will eventually return. Protecting exposed masonry externally is one of the most effective ways of preventing penetrating damp long term.
Myth 7 - “Rising damp doesn’t exist”
There is a lot of misinformation online claiming that rising damp does not exist at all. While some damp problems are incorrectly diagnosed as rising damp, genuine rising damp can and does occur in certain properties, particularly older homes with failed, damaged or bridged damp proof courses.
True rising damp happens when ground moisture travels upwards through porous masonry by capillary action. Common signs can include tide marks on walls, salt deposits, decaying skirting boards and dampness concentrated at lower wall level.
However, not every low-level damp issue is rising damp. Penetrating damp, high external ground levels, leaking gutters, condensation and internal moisture can often produce similar symptoms. This is why a proper inspection and accurate diagnosis are essential before carrying out any treatment.
Since 1875, UK building regulations have required properties to be constructed with a damp proof course designed to help prevent ground moisture rising through the walls. However, over time these systems can deteriorate, become damaged or bridged by external ground levels, render or plaster, which can allow moisture to bypass the original protection and lead to genuine rising damp issues.