The “capillarity”
is a physical-chemical phenomenon due to the molecular interactions between a liquid and a solid. Due to their dipolar nature, the water molecules are attracted by electrical forces inside microscopic channels called capillaries which originate the transport of the water itself from the foundations to the surface of the masonry, from which it will later emerge by evaporation.
The phenomenon of capillary absorption is inversely proportional to the diameter of the “vase”, or in the case of masonry bodies, to the width of the porous cavities, the size of a hair.
During its upward journey, the water dissolves and transports the salts encountered in the path, present in the ground and in the masonry, which are one of the main causes of the deterioration of the plasters.
The rising damp stops where capillary adhesion and gravity balance. The height of the ascent, reached by the water, depends on the type of material, the thickness of the masonry, the evaporation rate and the geographical area.
Depending on the nature of the soil, the probability of the phenomenon of capillary rising and its extent changes. A clayey soil, for example, offers a considerable capillary “push”, as well as not draining rainwater. In this case, the foundations are forced to continuous contact with the soil moisture. Otherwise, a gravelly ground can never be a vehicle for capillary rising damp, as it drains.
Note:
To favor the capillary rising humidity, the bodies and/or the wall enclosures must be made of porous but not macroporous materials; discontinuous sack masonry certainly cannot give rise to the phenomenon; on the contrary, in a masonry made up of compact, not very porous materials, rising damp can occur through the bedding mortars.
Salt manifestations (efflorescence and subflorescence)
As described above, during the “suction” process that causes the rising water
, the masonry is “invaded” by saline substances
, dissolved in the water contained in the capillaries.
When the water reaches the surface of the masonry and evaporates, the, the salts crystallize
.
If crystallization occurs near the surface, it determines the formation of clearly visible white spots, defined with the term “saline efflorescence”, if instead occurs between wall and coating, the crystallization pressure
of the salts can cause tension states (slightly expansive) able to prevail on the resistance of the materials. In this case we are in the presence of “saline sub-efflorescences”.
Sometimes a humid day may be enough for the highly hygroscopic salts to attract atmospheric water vapor, leaking onto the surfaces of the plaster, forming visible halos with chalking of the paints.
Another negative peculiarity of the salts is given by the possibility of the same, to keep the masonry in constant humidity, even in the absence of the rising phenomena that activated the process.
Products and technologies to use
Among the possible restoration interventions recognized as effective against capillary rising damp, according to the actual needs to be assessed case by case and always taking into account that the essential condition for drying the wall occurs only when the quantity of water which can evaporate is higher than the ascending one, can be counted: the construction of HORIZONTAL CHEMICAL BARRIERS and the construction of DEHUMIDIFYING MACROPOROUS PLASTERS. Where necessary, the construction of both systems. Further interventions are essentially attributable to cutting the masonry and electrophysical systems with multi-frequency.
The “Electrophysical Dehumidification of Protech Dry masonry” is a wall dehumidification system based on the technology of “multi-frequency pulses”. The installation of the appliance is carried out by expert personnel by means of appropriate fixing to a wall and then connection to a common socket. The system generates, inside the masonry, an electromagnetic field that interacts with the water molecules, preventing them from rising. However, the combination of an appropriate cycle of macroporous restoration plasters with proven dehumidifying capacity is always recommended..
The correctly designed and constructed horizontal chemical barrier represents a valid protection against rising damp. The objective of the chemical barrier is represented by the interruption of the flow of water migration into the masonry, through the deep impregnation of a section of the masonry fabric, capable of stopping the rising water. The physical principle used is represented by the inversion of the meniscus of the water contained in the microporosity of the masonry suitably impregnated; in this way the water is deprived of ascending motility.
The procedure is based on the injection, in specially designed and made perforations, of specific preparations, in the form of solution or gel (cream), characterized by a marked impregnating, water-repellent and diffusive capacity. The execution, intended as the definition of the drilling network and the succession of the injection phases, must take place on the basis of a precise program defined in advance and the drilling network must be designed according to the condition of rising damp, as well as the morphological characteristics of the structure. Where possible, the product to be injected must be free from long catalytic waits.
From an operational point of view, the technique can be schematized in a first phase of predisposition of circular holes of suitable diameter, depth and location and a second phase represented by the injection, at low pressure or by slow diffusion, of the specific water repellent impregnation preparations.
From an operational point of view, the technique can be schematized in a first phase of predisposition of circular holes of suitable diameter, depth and location and a second phase represented by the injection, at low pressure or by slow diffusion, of the specific water repellent impregnation preparations.
How to make a horizontal chemical barrier:
- Based on the type of masonry, the chemical barrier is usually built on a horizontal line
; any vertical distance between two horizontal lines of holes
, if foreseen and appropriate, it will be between 10 and 15 cm. - The diameter of the perforations is generally small (10/15 mm) for low pressure systems while slow diffusion systems require holes with higher diameters (up to 30 mm).
- The perforations are carried out with an inclination of not less than 10°, at an average horizontal distance of about 12 – 15 cm (about 8 holes/linear meter).
- The depth, which varies with the thickness of the masonry, must however affect about 80% of the wall thickness.
- The intervention is generally carried out on the external side of the building (A), at the shortest possible distance from the sidewalk and/or from the pavement (about 10-15 cm)
- The case of structures with high wall thickness (generally greater than 45 – 50 cm) it is also necessary to operate from the inside to ensure the overall impregnation effect (B).
Depending on the nature of the materials that make up the wall (usually mixed, low or non-absorbent stone walls), the need to offset the heights of the holes in the wall may be required in order to achieve the best diffusive distribution of the impregnating material.
Low pressure and/or slow diffusion chemical barriers:
The most frequently used impregnation preparations include methylsilicone resins in solvent, silicone resins in solvent, silicone resins in water dispersion, hydrolyzable silane resins, oligomeric organosiloxanes, alkoxiloxanes in water and in solvent and the microemulsions of silanes monomers with low molecular weight. The injection of the specific water-repellent impregnation preparations can be carried out at low pressure (pumping), with slow diffusion at atmospheric pressure or with gel supplied in an extrudable cartridge. In both cases, the supply must reach full absorption by the wall (up to refusal).
- The low pressure injection, characterized by a higher intervention speed, requires, in addition to a careful choice of the pressure level most suitable for the wall morphology to be restored, also particularly careful controls, both in terms of homogeneity and completeness of the absorption that regarding the risk of possible dispersion of the preparation, through cracks and cavities not previously identified and subsequently filled and/or reclaimed.
- The slow diffusion method presents to a lesser extent the critical points mentioned but involves prolonged operating times.
The realization of the chemical barrier by inserting a concentrated silane-based cream is perfectly usable in solid masonry (stone, brick, tuff, sandstone, concrete) but can also be effectively used also in hollow brick blocks (honeycomb walls).
Consilex Barrier-A
Solution of special modified silicone resins, dispersed in water, hydrophilic in the application phase, water-repellent and water-repellent after reaction with atmospheric carbon dioxide, for the preparation of water-repellent solutions for the creation of chemical barriers against capillary rising in masonry.
Consilex Barrier-A
Solution of special modified silicone resins, dispersed in water, hydrophilic in the application phase, water-repellent and water-repellent after reaction with atmospheric carbon dioxide, for the preparation of water-repellent solutions for the creation of chemical barriers against capillary rising in masonry.
Consilex Inject Mauer
One-component silane-based system modified for the preparation, with the sole addition of water, of water repellent microemulsions for slowly spreading masonry injections against capillary rising damp or using a pump with low operating pressure (0.5 to 1.5 bar), specific for the construction of chemical barriers in masonry, brick, tufa, stone and mixed, of varied thicknesses.
Consilex Inject Mauer
One-component silane-based system modified for the preparation, with the sole addition of water, of water repellent microemulsions for slowly spreading masonry injections against capillary rising damp or using a pump with low operating pressure (0.5 to 1.5 bar), specific for the construction of chemical barriers in masonry, brick, tufa, stone and mixed, of varied thicknesses.
Consilex Mauer Mono
Aqueous, water repellent microemulsion based on low molecular weight silane monomers, free from polluting solvents and reaction by-products, characterised by very high penetration and considerable reinforcing, protective effectiveness. It does not involve alterations in colour, appearance and breathability of the masonry structure. Suitable for forming horizontal chemical barriers against rising damp, free from awkward reaction waiting times.
Consilex Mauer Mono
Aqueous, water repellent microemulsion based on low molecular weight silane monomers, free from polluting solvents and reaction by-products, characterised by very high penetration and considerable reinforcing, protective effectiveness. It does not involve alterations in colour, appearance and breathability of the masonry structure. Suitable for forming horizontal chemical barriers against rising damp, free from awkward reaction waiting times.
Consilex Barrier Cream
Silane-based impregnating agent with gelatinous consistency for the formation of chemical barriers against capillary rising damp, particularly suited for new masonry, also cellular (refractory bricks, double uni, etc.). It is supplied in 600 cc aluminium-lined bags ("soft" cartridge), to be inserted in the appropriate caulking gun for sealants in bags.
Consilex Barrier Cream
Silane-based impregnating agent with gelatinous consistency for the formation of chemical barriers against capillary rising damp, particularly suited for new masonry, also cellular (refractory bricks, double uni, etc.). It is supplied in 600 cc aluminium-lined bags ("soft" cartridge), to be inserted in the appropriate caulking gun for sealants in bags.
The principle on which the technology of macroporous plasters is based is the achievement, through specific reactive agents of the porogenic type added to suitably designed mixtures, of significant increases in the normal porosity that characterizes traditional plasters (reduction of about 30% in weight compared to a traditional plaster).
The objective of the dehumidifying macroporous plasters is represented by the increase in the evaporation process of the humidity present in the masonry, in terms of speed and quantity, through the creation of an interface with a very high specific surface.
The dehumidifying macroporous plasters are in fact characterized by a uniformly distributed structure with alveoli (pores and micropores) which translates into a very high interface such that the evaporation towards the outside of the water of humidity contained in the support is extremely facilitated, while they remain the crystals of the salts dissolved in the liquid are kept inside. The transpiration in a free atmosphere allows to continuously dispose of the high quantities of water that the masonry has absorbed during its life, progressively increasing the quantities evacuated compared to those still destined to enter the wall facing.
The construction of effectively dehumidifying macro-porous plasters presupposes, as always, an adequate and rigorous preparation of the application substrates and must be informed and regulated by the best attention to preparation, application and curing.
Construction of macroporous dehumidifying plasters:
- In the presence of significant saline manifestations, it is necessary to preliminarily remove the relevance
and the adequate preparation of the substrates with specific products capable of neutralizing the reactivity of any residues (SANAREG). - Any degraded plaster that may be present must be carefully removed, up to a height of not less than 1 meter
, compared to the wet persistence line. - Given that the macroporous, dehumidifying plaster (SANATIGH / CALEOSANA / SANAWARME), must be applied in thicknesses of not less than 2 cm
, to improve the performance of the system in terms of adhesion, adherence and stability of the same, it is advisable to proceed with the application of a suitably breathable rough coat (UNTERSANA). - It is still necessary to provide as homogeneous application thicknesses as possible. Otherwise, accentuated differences in height can lead to cracking onset
, positioned in the thickness change zones. - In the presence of high application thicknesses (greater than 3 cm), it is necessary to use a fiberglass ARMAGLASS 160 (4 x 4 mm mesh – weight: 160 grams) or galvanized steel of small diameter and mesh (2 mm wire – 5 x 5 cm mesh), to be “drowned” between the layers of plaster. For further safety of any micro-cracks that could arise over time, the ARMAGLASS 160 fiberglass mesh (10 x 10 mm mesh – weight: 160 grams) is also recommended for smoothing plaster (SANASTOF).
Warnings and precautions for dehumidifying macroporous plasters
At steady state, in a macroporous plaster, the amount of evaporation water must be greater than the amount of rising water (A)
. By its nature and function, the dehumidifying macroporous plaster absorbs the water with which it comes in contact anyway; however, it cannot distinguish between the rising water in the masonry and that of contact with a puddle (B)
. For this reason, in external constructions, it is always necessary to provide suitable insulation devices, at the foot of the plaster, with respect to the sidewalk level and/or the flooring; a simple layer leaning against the wall can be enough (C)
.
As for the final painting, in order not to frustrate the breathability of the system, use certainly breathable lime based paints (SANAFARBE P), potassium silicates based (SANAXIL P) and/or siloxanes based (PROTECH SIL P).
Sanareg
Non-film reactive liquid based on an alkylsilane emulsion dissolved in water to be used for the inhibition of saline efflorescence in the dehumidifying restoration of masonry, by spraying or applying with a brush with rigid bristles. Sanareg penetrates into the capillary pores of mineral substrates and reacts with the hydroxyl groups encountered in its path, forming an invisible water-repellent barrier that does not allow water to escape to the surface, leaving the transpiration to water vapor unaltered.
Sanareg
Non-film reactive liquid based on an alkylsilane emulsion dissolved in water to be used for the inhibition of saline efflorescence in the dehumidifying restoration of masonry, by spraying or applying with a brush with rigid bristles. Sanareg penetrates into the capillary pores of mineral substrates and reacts with the hydroxyl groups encountered in its path, forming an invisible water-repellent barrier that does not allow water to escape to the surface, leaving the transpiration to water vapor unaltered.
Untersana
With the addition of mixing water only, this single-component premix creates a breathable, dehumidifying rough coating, preparatory to the application of restorative, dehumidifying, thermal-insulating and anti-condensation plasters, specifically Intosana, Sanatigh, Sanawarme and Caleosana, being plasters designed specifically for the healthiness of new buildings, existing buildings, works on green buildings and in the restoration of historic and monumental buildings.
Untersana
With the addition of mixing water only, this single-component premix creates a breathable, dehumidifying rough coating, preparatory to the application of restorative, dehumidifying, thermal-insulating and anti-condensation plasters, specifically Intosana, Sanatigh, Sanawarme and Caleosana, being plasters designed specifically for the healthiness of new buildings, existing buildings, works on green buildings and in the restoration of historic and monumental buildings.
Mauersan
Mauersan is a premix formulated with limes and hydraulic binders, microsilic with pozzolanic reactivity, selected aggregates in rational particle size distribution, light spheroidal aggregates of mineral nature (microporous amorphous silica), porogenic additives, hydrophobic agents. Mauersan, thanks to its network of intercommunicating pores, stimulates and accelerates the evaporation of the water contained in the damp walls, while blocking the transmission of liquid water from the inside of the walls to the outside. This dual functionality allows to obtain dry surfaces capable of accommodating various types of finishes, as long as they are highly breathable to water vapor.
Mauersan
Mauersan is a premix formulated with limes and hydraulic binders, microsilic with pozzolanic reactivity, selected aggregates in rational particle size distribution, light spheroidal aggregates of mineral nature (microporous amorphous silica), porogenic additives, hydrophobic agents. Mauersan, thanks to its network of intercommunicating pores, stimulates and accelerates the evaporation of the water contained in the damp walls, while blocking the transmission of liquid water from the inside of the walls to the outside. This dual functionality allows to obtain dry surfaces capable of accommodating various types of finishes, as long as they are highly breathable to water vapor.
Sanatigh
This macroporous, breathable, dehumidifying, fibre-reinforced plaster, with a base of natural hydraulic lime NHL 3.5, is for the dehumidification and hygrometric restoration of buildings and masonry, in works on green buildings, for new constructions and in the restoration of historic and monumental buildings.
Sanatigh
This macroporous, breathable, dehumidifying, fibre-reinforced plaster, with a base of natural hydraulic lime NHL 3.5, is for the dehumidification and hygrometric restoration of buildings and masonry, in works on green buildings, for new constructions and in the restoration of historic and monumental buildings.
Caleosana
A plaster for interiors and exteriors that is macroporous, in respect of green building standards, with high thermal insulation and anti-condensation performance, having a base of natural hydraulic lime NHL 3.5, siliceous aggregates, metakaolin, granular expanded silica with an extremely high volume of interconnecting voids and a low elastic modulus. Its particular characteristics make it suitable for dehumidification, for heat and humidity treatments on buildings and walls, in ecological building operations and in the restoration of historical buildings and monuments.
Caleosana
A plaster for interiors and exteriors that is macroporous, in respect of green building standards, with high thermal insulation and anti-condensation performance, having a base of natural hydraulic lime NHL 3.5, siliceous aggregates, metakaolin, granular expanded silica with an extremely high volume of interconnecting voids and a low elastic modulus. Its particular characteristics make it suitable for dehumidification, for heat and humidity treatments on buildings and walls, in ecological building operations and in the restoration of historical buildings and monuments.
Sanawarme
A thermal, external-coating macroporous plaster with high thermal and acoustic insulation, it has a base of natural hydraulic lime NHL 3.5, natural hydraulic binders with low soluble salt content and low environmental impact, botticino marble, kaolin, calcium casein, Vichy salt, calcium carbonate, tartaric acid, ammonium salts, expanded perlite, cork powder, natural fibres along wth specific and antisaline agents for the dehumidification, thermal and hygrometric restoration of buildings and masonry, in green building works, for new constructions and in the restoration of historic and monumental buildings. Specifically for applying “mineral coatings”. A mortar/plaster with guaranteed performance offering specific insulating properties pursuant to UNI EN 998/1 – Class T1 (the top thermal insulation class). Thermal conductivity certified pursuant to UNI EN 12664.
Sanawarme
A thermal, external-coating macroporous plaster with high thermal and acoustic insulation, it has a base of natural hydraulic lime NHL 3.5, natural hydraulic binders with low soluble salt content and low environmental impact, botticino marble, kaolin, calcium casein, Vichy salt, calcium carbonate, tartaric acid, ammonium salts, expanded perlite, cork powder, natural fibres along wth specific and antisaline agents for the dehumidification, thermal and hygrometric restoration of buildings and masonry, in green building works, for new constructions and in the restoration of historic and monumental buildings. Specifically for applying “mineral coatings”. A mortar/plaster with guaranteed performance offering specific insulating properties pursuant to UNI EN 998/1 – Class T1 (the top thermal insulation class). Thermal conductivity certified pursuant to UNI EN 12664.
Sanastof
A premix with a composition of breathable minerals for dehumidifying, with a base of natural hydraulic lime NHL 3.5, microsilicas with pozzolanic activity, selected aggregates, high tenacity microfibres and inert light unit weight thermal-insulating aggregates with a low elastic modulus. It is used for skimming and smoothing, both indoors and outdoors. This product is perfectly compatible with multiple substrates: lime-based plasters, lime cement, cementitious mortars, concretes, porous stone and brick. Its characteristics render it particularly suited to green building works and for restoring historic and monumental constructions. The maximum grain size of the aggregate is 0.9 mm.
Sanastof
A premix with a composition of breathable minerals for dehumidifying, with a base of natural hydraulic lime NHL 3.5, microsilicas with pozzolanic activity, selected aggregates, high tenacity microfibres and inert light unit weight thermal-insulating aggregates with a low elastic modulus. It is used for skimming and smoothing, both indoors and outdoors. This product is perfectly compatible with multiple substrates: lime-based plasters, lime cement, cementitious mortars, concretes, porous stone and brick. Its characteristics render it particularly suited to green building works and for restoring historic and monumental constructions. The maximum grain size of the aggregate is 0.9 mm.
Sanafarbe P
Breathable, natural, non-toxic paint, for internal and external surfaces, diffusive type, based on lime putty. Mineral-based, active formulation, high natural anti-mildew and anti-condensation capacity, prepared according to the traditional recipes, for use in ecological building interventions and in the restoration of vintage buildings and monuments.
Sanafarbe P
Breathable, natural, non-toxic paint, for internal and external surfaces, diffusive type, based on lime putty. Mineral-based, active formulation, high natural anti-mildew and anti-condensation capacity, prepared according to the traditional recipes, for use in ecological building interventions and in the restoration of vintage buildings and monuments.
Sanaxil P
Breathable, natural, non-toxic paint, for external and internal surfaces, for adhesion and microcrystalline structure, based on stabilized potassium silicate. Mineral-based, active formulation, with high natural mildewcide and anti-condensation properties, prepared according to the traditional recipes, for use in ecological building interventions, new buildings and in the restoration of vintage buildings and monuments.
Sanaxil P
Breathable, natural, non-toxic paint, for external and internal surfaces, for adhesion and microcrystalline structure, based on stabilized potassium silicate. Mineral-based, active formulation, with high natural mildewcide and anti-condensation properties, prepared according to the traditional recipes, for use in ecological building interventions, new buildings and in the restoration of vintage buildings and monuments.
Protech Sil P
Water-repellent, breathable, pigmented paint based on siloxane resins in water dispersion for painting and renovating civil and industrial buildings, and newly manufactured, for both external and internal facades. Recommended as a breathable, water-repellent protective finish for macroporous dehumidifying plasters (Sanatigh, Sanawarme, Caleosana).
Protech Sil P
Water-repellent, breathable, pigmented paint based on siloxane resins in water dispersion for painting and renovating civil and industrial buildings, and newly manufactured, for both external and internal facades. Recommended as a breathable, water-repellent protective finish for macroporous dehumidifying plasters (Sanatigh, Sanawarme, Caleosana).