Electrophysical drying of masonry affected by rising damp

The DRYMAT® system was developed to limit rising damp in masonry. It works with permanently installed electrodes and a regulated weak direct current. The design is prepared individually for each building and is accompanied by documented quantitative measurements of the moisture in the building material itself.

Damp walls can have many different causes. Water can enter a building by various routes – for example as a result of a drainage problem, a leaking water pipe, damaged waterproofing, pressurised groundwater, water penetrating from the side, condensation or inadequate ventilation.

Establishing the cause precisely is decisive, because different kinds of damp call for different approaches. The appearance of damp patches, mould or ruined plaster is therefore not in itself enough to determine the cause.

The first and most important step is a professional inspection and diagnosis.

Once we have located the source and the diagnosis confirms that the problem is rising damp and that the particular masonry is suitable for the method, we can offer the electrophysical DRYMAT® system – with individual design, professional installation and subsequent control measurements.

How can you recognise a damp problem yourself?

Typical signs of damp in masonry are visible damage around the plinth, salt deposits (efflorescence), blown and falling plaster, discolouration or a smell of mould.

These signs do not, however, prove in themselves that the cause is rising damp.

Common signs are:

• White crystalline deposits (efflorescence) – white patches or crystals on the plaster and the masonry, caused by salts that the damp carries to the surface.
• Damaged plaster and paint – blowing, flaking, crumbling, cracking or recurring patches in the lower part of the wall.
• A damp line – the damp and the patches on the wall usually follow a clear, horizontal, wavy line.
• An unpleasant smell of damp or mould – particularly in cellars, garages, storerooms and other rooms with inadequate ventilation.
• Cold wall surfaces – the walls are unusually cold to the touch, even when the room is heated.
• The appearance of mould – dark patches or other visible traces of mould, particularly in the lower part of the walls.
• Damaged skirting and floor coverings – parquet, laminate and other coverings lifting, swelling or distorting.
• Corrosion of metal elements – accelerated rusting of metal parts, pipes, fixings and other components.
• Raised humidity in the room – persistently high air humidity and frequent condensation on the windows.

It is important to know that these signs show that damp is present, but do not in themselves prove that the cause is rising damp.

Raised air humidity or condensation on the windows can also be caused by ventilation and heating habits, thermal bridges or other sources of moisture.

Leaking pipes, pressurised groundwater and problems caused solely by condensation must be investigated and dealt with separately.

What is rising damp?

Rising damp (often called simply capillary damp) is a physical process in which groundwater climbs upwards through the pores and microscopic channels (capillaries) of building materials such as brick, concrete, stone, mortar and jointing compounds.

The phenomenon works on the same principle by which liquid climbs a lamp wick or soaks into kitchen paper – the surface tension of the water „pulls“ it upwards against the force of gravity.

Capillary damp appears mainly on the ground floors, in the cellars and in the basements of buildings. Its principal cause is the absence or the failure of waterproofing (horizontal and vertical) between the foundations of the building and the surface of the ground.

Water from the soil carries dissolved mineral salts with it. When the water evaporates out of the wall, the salts remain on the surface as a white powder or fluff.

The salts crystallise and expand inside the pores, which literally destroys the structure of the plaster, making it blow and fall away. Simply repainting or replacing the plaster therefore often fails to solve the problem lastingly if the cause of the wetting is still present.

The damp usually reaches a height of 0.5 to 1.5 metres above ground level. In rare cases – with very fine capillaries, a high water table, or depending on the type and the covering of the plaster – the damp can reach higher.

The point at which the water stops rising is called the „evaporation line“ – there the rate of rise equals the rate at which the water evaporates into the air.

The right solution starts with an analysis of the causes

External waterproofing, drainage, mechanical horizontal barriers and chemical injection all have their appropriate fields of application.

Depending on the building they may be necessary, technically justified or economically worthwhile. They are often bound up, however, with large-scale intervention, excavation work or changes to the structure of the building.

The DRYMAT® system offers an electrophysical alternative where rising damp has been established and the masonry is suitable for the procedure.

In many cases the measure can be carried out from inside, without exposing the external walls. Whether further waterproofing, plastering or ventilation measures are needed is determined individually for each particular property.

How does the DRYMAT® system work?

Anodes are installed in the masonry, and the cathodes are placed deeper and further out, or below the level of the wall that is to be protected.

The control unit generates a regulated direct current in the low-voltage range. In this way an electric field is created within the damp, ion-bearing pore system of the masonry.

The ions dissolved in the pore water move within the electric field. Under suitable structural and material conditions, the upward transport of moisture is thereby limited and the moisture is influenced in the direction of the lower-lying cathodes.

In physical terms it is the dissolved ions and the electrokinetic processes in the pore structure that are decisive; the neutral water molecules themselves are not positively charged.

The system does not form a solid, physical barrier layer. It acts as an active electrophysical barrier and has to remain switched on for the effect to be sustained.

The moisture value that can be achieved and the length of the drying depend, among other things, on the structure of the wall, the thickness of the wall, the salt content, the initial moisture, the indoor climate and any additional sources of water.

Technical components for long-term operation

Titanium electrodes activated with precious metals

The electrodes are made of titanium and carry a corrosion-resistant, electrochemically active layer of, or based on, the precious metals iridium or platinum.

The remaining current-carrying titanium components are likewise specified for permanent use.

A resistor ahead of each anode

Each anode has a resistor connected ahead of it. It limits and distributes the current, reduces the differences between individual anodes and protects against excessive local current output.

Titanium connections

The cables, the screw connections and the electrodes are joined with corrosion-resistant, mutually compatible titanium components.

This reduces the material-related risks of contact and corrosion.

A special anode mortar

The anodes are installed with an electrically conductive, pH-buffering special mortar.

It secures lasting contact with the masonry and counteracts local acidification in the zone of the positive anode.

Conventional repair or masonry mortar must not be used for this purpose.

An adjustable control unit

The control unit supplies the electrode circuit with low direct voltage and allows its operation to be checked.

The output is specified in accordance with the system and the particular property.

The plan for diagnosis, installation and subsequent monitoring

1. Building diagnosis

The presentation of the damage, the damp line, the salt content, the structure of the wall, the ground and soil conditions and any leaks or water penetrating from the side are assessed first.

Thermography and electronic measuring instruments can help with orientation, but they do not replace a quantitative sample of the material.

2. Documented initial measurement

To secure a comparable series of measurements, the CM method (the calcium carbide method) with material taken from the masonry is preferred.

The sampling points are documented with their position and their height.

Salts or surface condensation can distort purely electrical surface measurements.

3. Property-specific planning

The height of the anodes, the spacing between the electrodes and the placing of the cathodes are determined on the basis of the damp and salt line and of the structure.

Where the damp reaches higher, a second anode level may be required.

The cathodes are always placed deeper and further out than the anodes.

4. Installing the anodes

Narrow channels (chases) and boreholes are formed.

The activated titanium electrodes are connected to the titanium conductor through their respective protective resistors and are installed tightly and in good contact using the specified pH-buffering anode mortar.

5. Installing the cathodes and commissioning

The cathodes are installed according to plan in the soil or below floor level.

The control unit, the conductors and the electrical values are then checked and the system is commissioned with the necessary documentation.

The cathode is a system electrode and must not be confused with the protective conductor (the earth) of the electrical installation.

6. Control measurement

A reliable comparative measurement is usually carried out after 6 to 12 months.

A new sample hole is drilled for the purpose at a similar place and at the same height.

Depending on the property, interim checks can also be agreed in addition.

The limits of the method and the accompanying measures it requires

The DRYMAT® system is intended for cases of rising damp. It is not a solution for every kind of wetting.

• DRYMAT® is not a substitute for repairing damaged pipework, leaking roofs, flooding or pressurised groundwater. Pure condensation damp likewise cannot be removed by electrodes in the masonry. Such causes must be investigated and dealt with separately.
• Salts already present in the masonry or the plaster do not automatically disappear entirely. Old plaster that is badly damaged or saturated with salts may have to be removed and replaced with a suitable plaster system. A separate desalination measure can also be useful.
• During the drying, the moisture is released into the rooms as water vapour. Proper ventilation and heating are important for that reason. The air humidity in the room may rise temporarily; in particular situations a dehumidifier may be needed for a time.
• Mould must be assessed professionally and remediated where necessary, whatever the drying method. Removing the cause of the rising damp can reduce the risk of mould appearing, but it does not replace cleaning it away or a health assessment.

Warranty and guaranteed services

The scope of the warranty, its term, the target values, the measurement methods, the maintenance conditions and the exclusions are set out in writing in the relevant quotation or contract.

Depending on the product and the agreement, warranty terms of up to 20 years can be offered for certain hardware components.

The warranty applies exclusively to the services and conditions stated in it. Other causes of damp, and the complete removal of salts already present, are not automatically covered by it.

DRYMAT® Systeme and ProKanal EOOD

DRYMAT Systeme GmbH was founded in 1997 in Saxony and has many years of experience in the electrophysical drying of masonry.

The method is applied to private, commercial, public and historic buildings. The published references include the State Hermitage in St Petersburg.

ProKanal EOOD is a trained DRYMAT partner in Bulgaria.

The design and the installation are carried out in accordance with the technical specifications of the manufacturer.

Standards, evidence and transparent classification

TOP 100 Innovator

DRYMAT was recognised in 2016, 2018 and 2025.

What is assessed is the innovation management of the company; the award is not a product certificate and does not replace property-specific evidence of effectiveness.

ÖNORM B 3355-2

The Austrian series of standards governs measures for limiting rising damp in existing masonry.

Part 2 covers, among other methods, electrophysical potential-reversal procedures using electrodes.

ÖNORM is a technical standard and is not automatically legally binding in every EU member state.

German patent

DRYMAT Systeme GmbH holds German patent DE 10 2017 119 134 for a system and method for dehumidifying, or draining (drying), masonry.

ISO 9001:2015

The quality management system of DRYMAT Systeme GmbH is certified to ISO 9001:2015.

This certification relates to the corporate processes and the quality processes; it is not a guarantee of a particular result in any individual building.

Expert opinion from OFI

A property-specific expert opinion from OFI Technologie&Innovation GmbH, dated 2016, establishes the effectiveness of a DRYMAT system at the reference property examined.

The result relates to that particular property and does not constitute a general product certificate.

A consultation for your building

ProKanal EOOD inspects the damage, identifies the causes and prepares a property-specific proposal.

Only after the diagnosis can it be judged whether the DRYMAT® system is a sufficient solution on its own or has to be combined with other building measures.

Start with a diagnosis, not with assumptions.

Get in touch for an inspection and an assessment of your building.