What is the capillary rise of water in the building?
The process of capillary rise is expressed in the rise of water through the walls of the basement or other underground structural elements, causing moisture in the premises. Depending on the composition, connectivity and size of the pores in the material, water rises more or less, causing moisture by capillarity.
Materials such as brick, wood and poorly compacted concrete have a porous structure that allows moisture to rise in height.
The chemical composition of moisture contains more or less mineral salts, which are deposited on the surface of the wall during its evaporation. A clear sign of this process are changes in the color of the wall, most often lightening.
If you notice wet spots on the walls near the floor, most likely your home is affected by capillarity. The height that wet spots can reach depends on factors such as:
- groundwater level and its seasonality
- materials used in construction
- temperature, humidity and ventilation of the premises
- conditions for the transfer of moisture from the wall to the room
- presence of salts and their crystallization on the wall surface
- previous interventions aimed at limiting the humidity in the premises
Capillary moisture occurs in walls that are not well insulated in the base or where there is damage, or not well executed waterproofing. High groundwater in many regions is year-round, which creates conditions for intensive development of mold, mildew, accompanying unpleasant odors and poor appearance of the premises.
What are the risks if we do not solve the moisture problem?
Increased humidity is expressed in wet spots, swelling of the plaster, separation of pieces of it, change in the color of the walls, the formation of mold, mildew and odor, rot of flooring and furniture.
In addition to the purely aesthetic negatives, the increased humidity in the walls and rooms poses serious risks to the health of their occupants. Constant exposure to spores from molds and toxic substances released during metabolism, as well as high humidity cause infectious diseases, allergies, asthma and even cancer.
Another much overlooked effect of long exposure to capillary moisture in the building is the weakening of the materials from which it is built. Corrosion and reduced mechanical properties are not observed not only in steel and wood elements, but also in those of concrete and brick.
When water evaporates on the surface and inside the wall, salt deposits are formed. The process of passing the capillary moisture through the structure is accompanied by the extraction of chemical elements from the composition of the building materials, which significantly reduces their mechanical properties. Clogging the surface pores with salts creates additional hydrostatic pressure and separates the plaster from the walls. Also, over time, there is an increase in the level of wetting in the wall. High humidity significantly increases the thermal conductivity of materials, which increases the cost of heating and cooling.
Neglected over time, such processes significantly reduce the quality of the building and its life.
What are the possible solutions?
Improving ventilation
Artificial ventilation of the premises and the installation of dehumidifiers in some cases solve the problem by drying the surface layer of the affected areas, which stops the development of mold and mildew. In the case of small amounts of moisture passing from the soil to the underground parts of the building or moisture generated during the operation of the premises themselves (laundry, sanitary facilities, etc.), it can be said that this approach is quite successful and most cost-effective. . But not universal! When it comes to intensive penetration of moisture from groundwater, the effect of air drying is enhanced water filtration and acceleration of the dangerous processes of chemical corrosion in materials.
Treatment of capillaries in the material
The sealing of the capillaries is done by various technologies, mostly according to the material from which the wall is made and its condition immediately before the repair. Basically, the methods differ depending on the pressure with which the irrigation with mineralizing liquid is performed. Highly porous materials such as clay masonry can be treated without pressure, while relatively thicker concretes require forced pressure. It is necessary to achieve a watertight internal barrier throughout the cross section of the element. Polymerization products use different chemical elements, but the general principle is to reduce the number and size of capillary pores. The newly formed chemical compounds have a strong hydrophobic effect.
Execution of waterproof plaster / screed / membrane
The composition and properties of some materials do not allow the application of the above method. When it comes to underground parts of the building, access from the outside of the affected areas is also often very difficult. Then there is the possibility of sealing moisture in the wall by building a watertight barrier on the inside of the base of bitumen, cement mortar and others. Such a solution is most often offered by masters and manufacturers of waterproofing materials.
Significant disadvantages of such an approach are the short-term effect of most systems, as well as the concealment of the problem without it being actually solved. The development of mold and mildew continues, and the construction of the building inevitably weakens over time. The repeated implementation of the waterproofing and the accompanying finishing costs seriously call into question the profitability of these repairs.
Drainage systems
Building a drainage system is a more expensive solution, but it also has its undeniable advantages. A well-executed drainage system could function smoothly for decades, fully protecting the building and its internal parts from the action of groundwater. The sanitary and hygienic conditions, as well as the thermal insulation indicators of the underground part of the walls are significantly increased. In certain cases, the drainages can also be used for partial stabilization of the soil when the foundations sink. The depth of laying the drainage pipes depends on the external dimensions of the building and the soil characteristics.
Unfortunately, in search of the lowest price, owners often come across contractors offering compromise solutions and ultimately need to rebuild a new drain. Saving on a geotextile membrane, shallow laying of drainage pipes and the implementation of a backfill with ordinary soil doom the enterprise to failure. Although in rare cases, the implementation of partial drainage on one or two of the facades can lead to uneven subsidence and structural problems for the house. The lack of geotextile and the backfilling of the backfill with uncompacted soil cause movements in the soil, respectively in the foundations of the nearby buildings. Within a few years after laying the drainage, the foundations yield, forming oblique cracks in the walls.
Another important point in the implementation of larger drainage activities is the performance of hydrogeological research. The information from it serves for reliable design of the drainage system with a minimum volume of excavation works. The results of the geological report can also be used in future fortification activities.
Ultimately, the choice of solution is individual for each site. The competent determination of the amount of damages, their specifics, the technical possibilities for manipulations on the materials, the proposed repair options, the purpose of the premises and the investor's desire to maintain the building are the key factors. They determine to what extent and for what period of time each construction problem will be solved.