Grocic hydro-isolation – hydro-isolation in Belgrade and Serbia:
- Roof hydro-isolation
- Flat roof hydro-isolation
- Terrace hydro-isolation
- Swimming pool hydro-isolation
- Garage hydro-isolation
- Basement hydro-isolation
- Cellar hydro-isolation
Roof, terrace hydro-isolation...
Concrete is one of the most economical construction products thanks to its longevity. However, concrete is still subject to wear and water damage. The lifespan of concrete depends on its water resistance. In most cases, water is the carrier for harmful chemical such as chloride salts, sulfites, bases, acids and many others which can damage concrete. Water can exit the concrete and vaporize, leaving behind salts and bases that react with dye and leave stains. Concrete hydro-isolation is the main part of constructing concrete buildings. The price of terrace hydro-isolation is calculated per 1m2 and depends on the type of materials installed and how long the written guarantee lasts (1-20years).
How to reduce gaps in the concrete before installing terrace hydro-isolation:
- Gel pores are formed because of cement hydration. These pores are very small, with a radius of about 2 nanometers and they don’t depend on the cement to water ratio.
- Capillary pores (0,05 to 1 micron in diameter) occur because of too much water present in the cement mixture and they do depend on the cement to water ratio.
- Trapped cavities that maintain the design of the concrete mixture, setting up the concrete and the method of care.
Seeing how the diameter of gel pores is so small, water can’t breach them. The second and third categories are relevant to the concrete hydro-isolation problems. Capillary pores are larger and do allow water to pass. Controlling the ratio between water and cement by using water-reducing additives can reduce these capillary pores. During the cement hydration process, some of the capillary routes become progressively blocked by the hydration reaction of gel-like products. This gel has very low hydraulic permission and if the ratio between water and cement is significantly low (below 0,5) the gel volume will be enough to fully block the capillary pores.
In the third category, the captured cavities are formed for the following reasons: bad design in the concrete mixture, irregular degradation of aggregates, inadequate compression, excess spoilage and segregation, very high or very low processing ability due to bad production. Sometimes cracks can occur and water can pass through and damage the steel armature within or the coloring. This is why hydro-isolation is an important part of the construction process and provides various advantages:
- The lifespan of your buildings will be significantly extended
- Frequent repairs or object maintenance will be reduced greatly
- The lifespan of the colors in the interior and exterior will be significantly improved
- The aesthetic appearance of the object will last for much longer
- There will be fewer health hazards.
If we consider the expenses of efficient hydro-isolation, it ranges only between 0,5 to 2% of overall construction expenses which is truly negligible! Hydro-isolation of a concrete construction is done in two phases.
The first phase occurs during the construction and the second after. The most efficient, economical and best quality isolation is done during the construction process itself.
There are so many different kinds of hydro-isolation materials in our market that people can be confused how to select the best material to apply. However, for the sake of simplicity, we can categorize these materials according to their time of use. Firstly, some materials are used for hydro-isolation as a preventive measure and secondly, some materials are used if moisture appears or there is a water leakage.
We will present those types of hydro-isolation used during construction.
Integral cement hydro-isolation products.
These products are mixed into the concrete or plaster when water is added in order to reduce water permissiveness. In normal conditions, they can provide anywhere between 25 to 90% of water resistance for constructions. There are several types of hydro-isolation available in our market. Additives for reducing the water amounts will reduce the water content in concrete without changing its handling properties, which results in less permissive, thicker concrete.
Materials with very fine particles – are very useful if the concrete mixture has a smaller percentage of cement and if it’s in deficit with fine aggregate. However, in good concrete mixtures it can have a reverse effect because adding fine particles increases the need for water which leads to less dense concrete with less pressure resistance. These fine particles block up the capillary pores while solidifying the cement mass.
Hydrophobic/water-repellant agents – the materials in this group reduce the water passing through dry concrete that would normally occur because of the capillary effect rather than exterior water pressure. It is believed that all these materials impose water-resistant properties on concrete surfaces as well as layering and in some cases pore blockage.
Airant agents – have a similar effect as water-reduction additives, improving the handling of the mixture and thus allowing for less water to be used. Micro-bubbles introduced into the cement mass will block the capillary pores. But, care must be taken not to overuse them. Overuse of airant agents will significantly reduce concrete firmness.
Selecting and applying materials
Given the diversity of possible applications and the vast selection of hydro-isolation additives, selecting a certain hydro-isolation material requires careful consideration.
Many concrete constructions are made to store water or maintain dry condition within the structure when it’s exposed to water from the outside. Seeing how concrete is not always completely water-proof despite the use of integral waterproof solutions as well as the fact that concrete develops smaller cracks after it has been set up, sometimes a barrier is needed that will cover the concrete surface in order for it to resist the water breaching under hydro-static pressure and/or capillary elevation. There are various barriers available in the market, but the most frequent and popular products are listed below:
Protection based on elastomer SBS stripes
This is one of the cheapest and highest quality as well as the most compatible ways to handle and hydro-isolate roofs, terraces, bathrooms...modified meltable stripe is used as a hydro-isolation layer. Also the fabrics with polyester felt and melted elastomer are massively used to protect concrete from water damage. This type of hydro-isolation is long-lasting. Sometimes the elastomer is mixed with one or several polymers in order to modify its properties.
Recently factories began producing polymer-modified bitumen membrane (APP) sandwiched between synthetic fibers, polymer-modified PVC membrane, neopren rubber membrane...available in the market. These types of hydro-isolation are elastomere, water-resistant and long-lasting. They are available in rolls of various thicknesses and can be fully bonded with the surface or separated according to the manufacturer’s instructions. The PVC membrane is intended to be used in above-ground works involving hydro-isolation, while the TPO membranes are for roof works. When installing them it’s important that as little moisture as possible is present inside before setting PVC and TPO membranes.
There are certain polymers with very low viscosity which are used for hydro-isolation of concrete constructions. Most frequently chemicals are silicone compositions which are water-proof by nature. Some silicone compositions can water-soluble, highly alkaline and very cheap silicone salts. This type of material can generate white blemishes in the surface of the base without disrupting waterproof properties.
Sometimes the exteriors of buildings are not protected or decorated with stone, brick or decorative bricks. Most of these materials is subject to wear which means rain will be absorbed and water will be able to breach into the interior and create moisture and damage. Water is retained for a longer time inside corrosive surfaces. This facilitates the growth of algae, fungi and mold on the surface of the wall and aesthetic beauty will be lost very soon. Algae growth can be prevented if the surface is maintained with a layer of silicone spread which will not alter the surface texture.
Injection mass and additives
Cement injection mass is used to consolidate concrete. This type of materials is mixed with water and Injected into the damaged concrete with a jet. Before solidifying, this cement injection mass will expand and fill the cracks. But, in most cases there are injection masses that should be mixed with the cement when the water is added. This suspension is also injected like the above for the same purpose.
Cement polymer spreads
These products are available in three variations. The first and most common type is the single-component polymer emulsion which is mixed with cement at the construction site until its consistency is suitable for brush application.
The second variation is a two-component system, where one package is in liquid form and the other is in the shape of cement powder. When these two components are mixed, they result in a thick spread. The third variation is a single-component product based on cement that is mixed with various types of chemicals and fillers. This type of material should be mixed with water until hydro-isolation consistency is achieved.
All these spreads are usually applied to the surface using a brush, on the positive side of water pressure. These products are very water-proof and flexible in nature and they also won’t crack with the structure’s heat motion.
Polymer cement hydro-isolation system has special advantages compared to other systems given their versatility, low prices of maintenance, simple application, steam permissiveness, UV rays resistance and much more.
As of recently various kinds of polyurethane system spreads have been available in the hydro-isolation market. One is a two-component system with or without diluters, which is chemically treated. The other is a single-component modified system based on tar. The main advantages of polyurethane hydro-isolation are better adhesion, elasticity and resistance against various harmful chemicals. Sometimes polyurethane foam (PUF) is used, cast on the spot in order to hyrdo-isolate roofs as well as for heat isolation. This system has special purposes. Most polyurethane spreads are not resistant to UV rays.
Complaints about poor hydro-isolation are more and more common and it frequently happens that the guilt is placed on the quality of the hydro-isolation materials. If we look at this another way, most cases show that the installed hydro-isolation materials have passed all the strict control checkups and quality tests. Most errors occur because of incorrect specifications, the human factor and poor craftsmanship.
This is why it’s very important to be vigilant in the initial face, when the specifications for the hydro-isolation are being set. When selecting the type of hydro-isolation they want, the person creating the project should use their experience and judgment, taking into consideration the severity of water breaching, weather conditions, type of construction and the conditions in which the materials will be applies. The producers should also be consulted when selecting the materials, the method of application, surface condition, number of spread coats, repairing cracks...in order to ensure satisfying performance of the hydro-isolation systems.
When creating specifications, the following points should be considered: the type of materials, the durability or life-span, the efficiency of its purpose, the ease of application, the ease of eventual repairs, compatibility with other materials, expenses and the effect it has on the environment. Hydro-isolation system should also be selected with the current condition of the building in mind, as well as thinking of the worst case scenario that might occur in the future. The system should not ignore the basics of the buildings and construction as well as the science of the materials themselves.
Guarantee – hydro-isolation
It’s common that the hydro-isolation works are done with a guarantee of quality from the contractors. It is a fact that a small number of them don’t fulfill their warranty obligations if a problem occurs. Therefore the contractors should pay attention to every aspect of the works they perform, especially that the works are being done by professionals.
The common tendency to spend as little funds as possible on hydro-isolation often leads to reduced specifications by the contractors so that they would get the job. This approach ruins the main point of the true hydro-isolation systems. A good hydro-isolation system is a collective and intellectual task, undertaken by the contractors, investors and architects together.
The presence of water in swimming pool walls can cause damages to the pool construction, even though colorful terminology is used in our market when hydro-isolation is involved.
Vertical hydro-isolation is done on the exterior of the swimming pool walls. It is applied on a previously smoothed surface which must be protected from mechanical damages from the outside. When setting this type of isolation, it is important to dig a wider area around the pool, about 80cm-1m.
In order to achieve the proper pool hydro-isolation it is vitally important to have a previously prepared surface. It must be dry, load-bearing and clean and can be made of various materials such as: brick, concrete, plaster, blocks and so on. The important thing is to remove any impurities from the base surface such as plaster remains, excess concrete and any kind of spread that can crumb away. The prepared surfaces are washed under high-pressure water streams or with a regular, mechanic procedure, then all the cracks are filled. The rest of the procedure depends on the quality of the walls, technical conditions and personal choice. There are many materials for hydro-isolation in our market and choosing the best one is one of the key factors for a healthy construction.
The most common case of post-construction hydro-isolation is also called ‘the negative side’ hydro-isolation. It is done on the interior of the wall, when the water from the exterior has found its way into the pool. The term is used when hydro-isolation is done from the opposite side of the wall to that which is exposed to underground water.
The parts where breaching or spilling occurs are most often the lines where the walls join the floor, as well as cracks. When solving hydro-isolation issues, it’s important to determine what kind of water breach is in play and determine the cause of the swimming pool weakening.
There are several types of resolving swimming pool hydro-isolation and their success depends on several factors, methods, situations and compatibilities... Sanation is often done using various penetrates and spreads under the principle of water-proof tubs. Depending on the situation, on the spot, the way of construction, applied materials, foundations, ground quality, underground waters, depth and previously done works, there are various ways of treating any problem with a broad array of products.
How to overcome water and moisture
How does water travel through buildings
Water enters and moves through and outside of buildings in four ways that we will explain in order of the amount included – this allows us to set our priorities when managing water in construction.
- Unified water – rain, snow, frost and other water sources guided primarily by gravity, but also influenced by wind and pressure differences. Unified water is managed on the exterior of the building by moving and guiding it downward, off and away from the building. On the interior, we manage unified water by preventing leakage and condensation.
- Capillary moisture is moving under tension through degradable construction materials or narrow canals between the materials. Primary defenses involve capillary interruptions in suitable places such as between the foundation, the fugue or any other moisture-sensitive material.
- The moisture transported by air enters or exits the building through air leakage. The air passes through holes in the building’s exterior, pushed by air pressure differences, the chimney effect or mechanical ventilation. When humid air hits a cold surface inside of the building, there can occur condensation.
For example, humid summer air can travel into the building through technical openings, canals and entrances in a breeze, into the facade surface. When the air reaches the interior side of the wall, cooled by air-conditioning, the moisture condensates on it. One of the ways we handle air-transported by air is by preventing air leakage with a continued air barrier.
- Steam diffusion is when water moves through the material depending on the contrast in relative humidity or steam pressure
Example – summer day with rain that soaks the exterior walls. Sun comes up, heats up the wall and the water evaporates into the building through the walls.
Guiding the steam movement is an arduous task – even though we would like to guide the steam within the objects, we would need to know how the steam-permissiveness of the construction materials enables the steam to move outside of the building. Even though the walls of the building may become soaked in either of these four ways, once the water is inside, the next step is figuring out how to get it out, which can only be done by diffusing.
What pushes the steam into the objects is the climate and seasonal changes – the steam from the interior of heated rooms in the winter and outside cooled rooms during summer. We have to balance the limitation of this climate and season-driven steam movement into the building with certain allowances in steam permissiveness into some of the materials. This is done by analyzing the steam profile or through hydro-thermal modeling.
Isolation limits heat passage which in turn reduces the possibility of drying out humid structures of the building. If we use a lot of isolation, we have to manage the steam movement with equal intensity.
Dejan Grocic – Grocicizolacije