ELECTROPHYSICAL DEHUMIDIFICATION OF MASONRY

The crypt of the Cathedral in Cremona

  

It has successfully completed an independent study on the effectiveness of the Electrophysics dehumidification system of walls with Genié. The research was conducted at the crypt of Santa Maria Assunta of Cremona Cathedral, damaged by rising damp, where the humidity conditions of the masonry are now back to physiological values.
Damage to plaster, salt efflorescence, stains and mold in the masonry of underground and groundfloors are often the result of the so-called rising damp inside walls. The crypt of the Cathedral of Our Lady of the Assumption in Cremona was affected by extensive damage caused by rising damp. In February 2013, the bishop of Cremona decided to choose, among various methods available in the market, the most convenient solution to counter the problem in such a wide a complex; Genié, a solution based on the innovative electrophysical dehumidification technology using “multiple frequency impulses”. A study conducted by Luigi Soroldoni (scientific advisor for cultural heritage and professor at “Aldo Galli“ Academy in Como) and Umberto Casellato (former Associate Head of Research with IDPA – CNR) demonstrated that the problem was eventually solved.

HOW GENIÉ WORKS
Genié generates an electromagnetic field inside the masonry, which interacts with the water molecules and prevents them from rising. Unlike other similar methods, which use monofrequency, Genié generates a train of impulses at different frequencies allowing to obtain guaranteed results on all types of masonry, regardless of the shape of their capillary pores and of their composition. Genié is installed by fixing it with four standard screw dowels and connecting it to a standard socket.
1_ Because water molecules are bipolar, they are attracted by electric forces into micro- scopic canals, also known as capillary pores.
2_Each molecule of water found in the ground can therefore migrate upwards through the capillary pores of the foundations into the walls of a building.
3_During its rise, water dissolves and carries with it any salts met on the way, which in turn are one of the main causes of plaster degradation.
4_The rise stops along a “0 potential” line, where capillary adhesion and gravity get balanced.
5_Here, the water found in the walls evaporates, it is released in the environment and replaced by more water rising from the ground.
6_Genié generates impulses capable of disturbing the electric forces of adhesion inside the capillary pores of walls.

With a constant and targeted work, the installation brings the “0 potential” line down, by pushing water back into the ground. This helps stop mold and avert all risk of masonry degradation.
 After the walls are rehabilitated, they can be brought back to their original state, with no further risks of plaster damage, salt efflorescence, stains, mold, etc.
Genié is totally safe and can be used in any living environment, even with children, old people or sick people. In fact, Genié generates an electromagnetic field inside the masonry, which does not interfere with human beings or with any electric or electronic appliances of sorts, including medical and sanitary apparels.

METHOD OF STUDY OF THE EFFICIENCY OF THE DEHUMIDIFICATION METHOD
Sampling was performed through measurements of the humidity (free water) content with the thermo-gravimetric method, by calculating the weight balance after water was eliminated by forced evaporation. Two samples of 3-5 g were collected in each examined area, by using a core-drill (18-20 mm wide), of which one at a depth of 0-10 mm and one at a depth of 50-150 mm, at floor level and at about 1.5 m above the floor, respectively. The samples were weighed with precision scales (sensitivity of 1 mg), stored in special glass containers and then put in a heater under controlled temperature (105° C) until they reached a constant weight.
The balance between the initial weight and the post-drying weight expressed as a rate of the dry material represents the value of humidity found in the sample.
 To allow any future measurements after the dehumidification process or any further assessments, the wall was plugged with some specially conceived small cotto bricks, whose water absorption capacity is similar to the old bricks, so that they may be removed with no need for further core-drilling.

HUMIDITY MEASUREMENTS AND CONCLUSION
In February 2013, before dehumidification works, the wall showed visible damage from rising damp, and namely portions of plaster lifting and peeling off, and powdering of the painted layers, which are all the result of water movements and, above all, of the exchanges with the inner environment during evaporation and condensation.
After 12 months of operation of Genié devices (1 device + 1 satellite installed on the south and on the north wall, respectively), moisture in the walls fell heavily, by as much as 70% in some cases; after 16 months, the dehumidification process brought the rate of humidity of masonry down to a range between 2% and 4% (physiological rate in masonry). Some humidity (10-16%) was still found in two out of 12 spots on the north wall.
After 16 months, the rates have stabilized at values of physiological humidity, except in the area A due to the sensitivity to interstitial condensation and the salt.
Although the effectiveness of Genie was already defined, in May 2016 was made one last measurement that showed the return of normal humidity values even in the most problematic area. To conclude, after the installation of Genié devices, the conditions inside the crypt improved sizably in general terms.

[by Martino Lorusso]