Introduction
Rising damp is a physical phenomenon that affects many buildings. It occurs when water contained in the soil rises by capillarity through porous walls, particularly when there is no damp-proof barrier between the foundations and the masonry.
Over time, this process leads to dark stains, peeling paint, salt deposits, and the gradual weakening of materials. Many homeowners discover this problem during renovation works or simply when observing visible damage.
This raises a frequent question: what solutions exist against rising damp?
There is no universal method suitable for every case. Approaches vary: some are traditional, others are more modern and non-invasive, such as ATE and ATG systems.
This article provides a detailed analysis of these solutions, explaining their principles, limitations, and role in managing rising damp.
1. Traditional Methods
1.1 Perimeter Drainage
Drainage is one of the first techniques used when a building is exposed to a strong presence of water in the soil. The principle is simple: evacuate excess water in contact with the foundations.
A trench is dug around the house, along the walls in contact with the ground. A perforated pipe is placed inside, surrounded by gravel and protected by geotextile. The collected water is then directed to an outlet: a sump, ditch, or stormwater network.
Drainage reduces hydrostatic pressure on the walls but does not completely eliminate rising damp. Even if water drains better, the wall remains porous and continues to absorb ground moisture. Drainage is therefore a complementary measure, rarely sufficient on its own.
1.2 Injection of Water-Repellent Resins
Injection is a widely used method in the renovation of old buildings. It consists of creating an artificial barrier within the wall to block the upward migration of water.
Holes are drilled at regular intervals at the base of the wall. A water-repellent product, usually a resin or gel, is injected either under pressure or by gravity. As it spreads into the capillaries, the product forms a barrier that prevents water from rising.
This technique can be effective if carried out properly and if the wall materials are suitable. However, it has limitations: its effectiveness depends on the porosity of the masonry, the regularity of the drilling, and the quality of the injection. In heterogeneous or compact stone walls, distribution may be insufficient.
1.3 Capillarity Cut (Sawing or Insertion)
This is a radical method. A horizontal cut is made at the base of the wall, in which a waterproof membrane is inserted, often made of stainless steel, bitumen, or polyethylene.
This physical barrier completely blocks water migration. However, in renovation, it is difficult to implement: it is costly, invasive, and may weaken old walls. Therefore, it is rarely used in existing houses and is more commonly reserved for new constructions, where it can be planned from the outset.
1.4 Special Plasters and Mortars
Certain plasters provide a complementary solution. They do not eliminate the cause but improve the appearance and breathability of walls.
Often based on lime or “macroporous” mortars, they allow moisture to evaporate without damaging the surface. They reduce visible stains, prevent bubbling, and promote surface drying.
However, they do not stop rising damp: they must always be combined with a deeper treatment.
2. Modern Non-Invasive Solutions
In recent decades, innovative solutions have emerged to limit rising damp without destructive intervention in the walls. They are based on different physical principles than traditional methods. Two main families exist: ATE (electromagnetic devices) and ATG (geomagnetic devices).
2.1 ATE: Electromagnetic Device
Every wall naturally generates an electrical potential difference with the ground, which encourages rising damp.
The ATE emits a very low-frequency electromagnetic field that reverses the polarity of the water present in walls. Water molecules reorient themselves and descend back toward the foundations. This process causes the materials to dry out progressively and naturally, without altering the building’s structure.
This is a slow phenomenon: the thicker and damper the wall, the longer the drying process takes. Unlike invasive techniques, ATE does not require drilling, injection, or cutting.
2.2 ATG: Geomagnetic Device
The ATG works differently. It requires no electricity and relies on the natural magnetic fields of the Earth to act on the water contained in walls.
However, it is important to emphasize that the ATG is not an equivalent alternative to the ATE. It is only used in cases where installing an ATE is impossible, such as in buildings without a permanent power supply or with specific technical constraints.
The ATG is therefore a secondary solution, considered only when an ATE cannot be installed.
2.3 Common Points and Differences
ATE and ATG share several characteristics:
- They are non-invasive.
- They do not require chemical products.
- No drilling, injection, or cutting.
- Discreet installation, compatible with occupied buildings.
The essential difference lies in their operation and field of application:
- The ATE, powered by electricity, acts directly through its electromagnetic field.
- The ATG, autonomous, uses natural geomagnetic fields and is chosen only when an ATE cannot be installed.
3. Precautions Before Choosing a Solution
3.1 The Role of Diagnosis
Before any intervention, it is essential to confirm that the problem is indeed rising damp. The symptoms may resemble those of other moisture issues, such as condensation or lateral infiltration. A thorough diagnosis, including measurements and analysis, avoids mistakes.
3.2 Adaptation to the Building
The choice of solution depends on the type of building and its constraints. A fragile old house cannot withstand a capillarity cut. A building without electricity cannot host an ATE, which may require the use of an ATG.
3.3 A Slow Process
Whichever method is chosen, wall drying is always progressive. The water accumulated in the masonry does not disappear quickly, but only with time.
4. Limits of the Different Approaches
4.1 No Immediate Solution
No method dries a wall instantly. All require time to work.
4.2 Importance of Ventilation
Even if rising damp is treated, a poorly ventilated building remains exposed to condensation and mold.
4.3 Combination of Solutions
It is common to combine several techniques: for example, drainage with an ATE, or a special plaster applied after installing a non-invasive device.
Conclusion
Rising damp is a natural but constraining phenomenon. Different solutions make it possible to limit or control it.
Traditional methods (drainage, injection, capillarity cut, specific plasters) have long been used, but they have limitations.
Modern devices ATE and ATG offer a non-invasive approach. The ATE acts through an electromagnetic field and is the preferred solution. The ATG, autonomous, is considered only when an ATE cannot be installed.
The choice of solution always depends on a precise diagnosis and an analysis of the specific conditions of each building.
