Introduction
Moisture is one of the main enemies of buildings. It can take many forms: façade infiltration, indoor condensation, leaking pipes, or a natural and persistent phenomenon: rising damp.
This results from the progressive migration of water contained in the soil into walls. Over time, it causes visible damage (stains, bubbling, efflorescence) and reduces indoor comfort.
To tackle this issue, different solutions exist. Traditional techniques (drainage, resin injections, capillarity cuts) have long been used. However, they are invasive and often difficult to implement. For this reason, modern, non-destructive systems have been developed: ATE (electromagnetic devices) and ATG (geomagnetic devices).
Although they share the same objective, these two devices are based on different principles and are not applied in the same contexts. This article explains the differences between ATE and ATG, starting with a deeper understanding of rising damp itself.
1. Understanding Rising Damp
1.1 A Natural Phenomenon
Construction materials such as bricks, stone, or mortar contain pores. When in contact with damp soil, these pores allow water to rise upwards, even against gravity. This is the law of capillarity.
The height reached varies: generally between 0.5 and 1.5 m, and in extreme cases up to 2 m.
1.2 Aggravating Factors
- Absence of a damp-proof course: common in older buildings.
- Soil composition: clay and silt soils retain large amounts of water.
- High water table: increases moisture pressure.
- Porosity of materials: bricks and soft stones absorb water easily.
1.3 Visible Signs
- Dark patches at the base of walls.
- Blistering and peeling of paint or wallpaper.
- Crumbling plaster.
- Salt deposits (efflorescence).
1.4 Long-Term Consequences
- Lasting aesthetic damage.
- Loss of cohesion in materials (mortar, bricks, stones).
- Cold-feeling walls and humid air.
- Increased heating consumption due to damp walls.
2. Limits of Traditional Solutions
Before discussing ATE and ATG, it is worth recalling that traditional solutions have long existed: drainage, injections, capillarity cuts, special plasters.
They can limit or block the phenomenon but present significant drawbacks:
- Heavy and invasive work.
- High costs.
- Difficult application in old or listed buildings.
It was in this context that ATE and ATG devices were developed.
3. ATE: Electromagnetic Device
3.1 Basic Principle
Every wall naturally generates an electrical potential difference with the ground, which encourages moisture to rise.
3.2 Operation
The ATE emits a very low-frequency electromagnetic field that reverses the polarity of the water in walls. Water molecules reorient themselves and flow back down toward the foundations. This process causes the materials to dry out gradually and naturally, without altering the building’s structure.
This is a slow process: the thicker and wetter the wall, the longer the drying takes.
3.3 Installation
An ATE is installed inside the building, without destructive works. It requires a permanent power supply and works continuously once in place.
3.4 Advantages and Limitations
- No drilling or injections.
- No chemical products.
- Preservation of the masonry.
- Dependent on electricity supply.
4. ATG: Geomagnetic Device
4.1 Basic Principle
The ATG relies on the natural magnetic fields of the Earth. Unlike the ATE, it does not require any electricity.
4.2 Restricted Use
It is important to note that the ATG is not an equivalent alternative to the ATE. It is only used when the installation of an ATE is impossible, for example in buildings without a permanent power supply or with specific technical constraints.
4.3 Advantages and Limitations
- Simple and discreet installation.
- Fully autonomous, no maintenance required.
- Smaller effective range compared to an ATE.
5. ATE and ATG: Common Points and Differences
5.1 Common Points
- Both are non-invasive.
- Neither requires chemicals.
- No drilling, injection, or cutting.
- Discreet installation, even in occupied buildings.
5.2 Differences
- Power supply: ATE requires electricity, ATG is autonomous.
- Priority: ATE is the preferred solution, ATG is only used when ATE is not possible.
- Principle: electromagnetic field for ATE, natural geomagnetic field for ATG.
6. The Importance of Diagnosis
Before any installation, an accurate diagnosis is essential. Moisture symptoms may also be due to condensation or lateral infiltration, not rising damp.
A thorough diagnosis includes:
- Visual inspection of damage.
- Instrumental measurements (moisture meters, probes, thermography).
- Salt analysis to determine the type of moisture.
Conclusion
Rising damp is a natural but problematic phenomenon that progressively degrades buildings.
Traditional solutions exist but are invasive and sometimes insufficient.
Modern devices ATE and ATG offer a different approach:
- ATE, which acts through an electromagnetic field, remains the priority solution.
- ATG, autonomous and based on natural fields, is considered only when an ATE cannot be installed.
Both pursue the same goal — to act on the capillarity phenomenon — but differ clearly in their operation and conditions of use.
