Permanent damp removal from masonry. Guaranteed.

Rising damp is water from the subsoil that climbs up through the capillaries of porous masonry — much like water in a sponge. It occurs when the horizontal damp-proof course at the base of the wall is missing, damaged, or worn out; a typical problem in older buildings constructed before modern standards. In standard brick masonry, it usually rises 50–150 cm, and in stone or mixed masonry, it can exceed 2 m, depending on the porosity of the material and the height of the capillary rise.

It is recognised by three typical signs: a horizontal "line" of damp parallel to the floor, white salt efflorescence on the surface (nitrates, chlorides, and sulphates dissolved in the ground), and seasonal variation — more pronounced in winter when water does not evaporate, and less visible in summer. The salts crystallise as the water evaporates and gradually break down the plaster from within, meaning that merely repainting hides the problem but does not stop it.

Condensation damp forms inside the room, not within the masonry. Warm air holds a certain amount of water vapour; when it hits a surface with a temperature below the dew point (typically a cold corner, a window reveal, or a thermal bridge), the vapour condenses into water. There are three key factors: indoor vapour production (showering, cooking, drying laundry, breath of occupants), insufficient ventilation, and cold surfaces caused by poor thermal insulation or an unheated room.

Characteristic symptoms include: mould in corners and around windows, droplets on glass, wet spots on external walls in winter, and indoor humidity constantly above 65%. In this case, the water does not come from the ground or the façade — it forms directly inside the house, so the solution lies in better ventilation, reducing vapour production, and increasing surface temperatures (insulation, heating).

Hydrostatic damp is water acting on the masonry under hydrostatic pressure — typically in basements and cellars below ground level, where the walls separate the interior from damp soil or reach below the water table. Water in the ground presses on the walls and floor of the basement and penetrates through the smallest cracks, construction joints and even the very structure of the concrete or masonry, if these are not waterproofed against pressurised water.

Symptoms: localised wet patches at any height (unlike the horizontal line of rising damp), drips or rivulets of water running down the walls, water in corners after heavy rain or in spring during the thaw. The term structural damp is used more broadly for all damp that enters the structure through a building failure — missing drainage, damaged external waterproofing, an unventilated basement. The solution is fundamentally different from rising damp: it requires intervention from the outside (drainage, waterproofing the walls against pressurised water, repairing rainwater downpipes). Injection at the base of the wall on its own will not stop hydrostatic water — it only addresses capillary rise.

They differ in the source of the water and the direction from which it enters the masonry. Rising damp climbs up from below through the capillaries of the masonry, out of the ground. Hydrostatic damp comes in from the side or from below under hydrostatic pressure (typically basements below the water table). Penetrating damp passes through the external wall — rain through a damaged façade, a cracked downpipe, a leaking roof. Condensation damp forms inside the room when damp air condenses on a cold surface.

Each calls for a different solution: rising — a horizontal barrier at the base of the wall (injection, sawing); hydrostatic — external waterproofing and drainage; penetrating — repairing the façade, downpipes or roof; condensation — ventilation, insulation, reducing vapour production. The worst mistake is to confuse the cause and treat the wrong type — the symptom disappears for a few months and the water comes back.

Three quick signals: the line of the damp (horizontal = rising, localised = penetrating), white efflorescence (a strong sign of rising damp), mould in corners around windows (a strong sign of condensation). When in doubt, take our short quiz or have the damp measured on site.

Salt from beneath the foundations rises with the water and crystallises on the surface as the water evaporates. Efflorescence is a diagnostic signal — if you can see it, the water really is moving through that wall. The salt also damages the plaster from within; merely repainting hides the problem but does not solve it.

Mould starts to grow when the plaster damp is above 70%, within 24–72 hours. The spores released into the air are allergens. In people with asthma or in small children, symptoms can appear within a few weeks. A damp wall is never just a cosmetic problem.

Dry brick has 5–10 times better thermal insulation than damp brick of the same thickness. The water in the pores conducts heat outwards. Buildings with an extensively damp basement typically use 20–30% more heating than the same buildings when dry.

Surface symptoms (efflorescence, mould) can be handled with cleaning and an anti-mould coating. The cause — water in the capillaries of the masonry — is not addressed by any coating or plaster. If you do not stop the source of the water, the damp returns within a few months. A permanent solution requires technology (WetBRICK® gel injection, for example, works for the long term).

It helps with condensation (humidity in the air). With rising damp it does not help at all — the water does not come from the air, it comes from the ground. Ventilation can only make the cold feel worse, because dry masonry would insulate better.