The Complete Guide to Demystifying Waterproofers

The needs of waterproofing in civil construction

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Waterproofing agents can be applied to solve different building watertightness requirements. There are several categories of humidity that can affect the building, each of which acts on different elements according to the type of exposure. Therefore, it is important to understand the main waterproofing needs in the various components of the structure, seeking to meet each of them in the most appropriate way. The main requests for waterproofing in civil construction are:

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Percolation water

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Percolation water in civil construction is the request that comes from rainwater or washing, for example. Thus, the main elements that must be protected from this type of moisture are walls, roofs and floors, which will be more subject to contact with percolating water.

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Capillary water

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Capillary water is what is known as the moisture that comes from the soil, which rises through the building elements through the capillarity. In this way, it directly hits structures that are in direct contact with the ground, such as the foundations themselves, curtains, and floors above the ground.

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Water under pressure

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We call pressurized water those situations in which there is a significant amount of water, causing the weight of the liquid itself to exert force against the elements that support it. This is the case of reservoirs and pools, for example, and the force can be unilateral - coming from only one side of the structure, or bilateral - coming from both sides of the element.

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Condensation water

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Finally, condensation water is what occurs when moisture in the form of vapor is transformed back into liquid. That is, it is recurrent in structures exposed to steam, cold or very humid environments.

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The types of waterproofing agents

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Waterproofers are divided into two main categories: rigid and flexible. This separation is very important to understand which are the best alternatives in each application and, for this, it is necessary to understand the concept of structural motion.

Every construction is subject to structural movements - especially thermal movements. Thermal movements are caused by the changes in temperature to which the building is exposed: when in contact with heat, the materials expand and expand, while in the cold they retract. This generates a change in volume, which grows and decreases according to the context.

To assemble a structure, several materials are combined, each with its specific characteristics and properties. This means that everyone will behave differently in the face of heat and cold, and some will expand and retract more, and others less. As a result, these movements can generate cracks and fissures in the encounters between materials, reducing the adhesion and integrity of the assembly.

While these movements are not necessarily a problem for other aspects of construction, the appearance of a single crack in the waterproofing can compromise the effectiveness of the entire system - after all, a small crack is enough for moisture to enter the interior of the structure. Therefore, this knowledge is essential when choosing your waterproofing agents between the categories:

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Rigid

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As their name suggests, rigid waterproofing systems are those that do not withstand large movements. The main characteristic of this type of waterproofing agent is the low ability to absorb deformations of the base, especially when it comes to concentrated deformations such as cracks and cracks.

Since rigid waterproofing does not keep up with thermal movements, cracks may appear, which leads to the appearance of waterproofing flaws through which water can seep in. Thus, they are only suitable for specific uses, in places with little or no movement.

In practice, this translates into elements with little exposure to the sun or buried elements, such as foundations, basements, elevator shafts, baldrame beams, and floors in direct contact with the ground, for example.

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Flexible

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The flexible systems, in turn, are able to better accompany the thermal contractions and expansions that the structures are subject to. Depending on the waterproofing system, flexible waterproofing agents are capable of withstanding base deformations with varying amplitudes - including cracks and cracks.

In practice, flexible waterproofing systems are the most used because of their versatility and practicality. In addition, there are several options when choosing the best one for each situation, which makes it easier to prefer this type of waterproofing.

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Technical standards for waterproofing

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Like any construction procedure, waterproofing systems are also guided by regulations developed by the ABNT, or Brazilian Technical Standards Association. In this case, the main rules to be followed are NBR 9574: Execution of waterproofing - Procedure, and NBR 9575: Waterproofing - Selection and design.

NBR 9575 focuses on selecting the appropriate type of waterproofing to be chosen for each project. It establishes the general design requirements, the specific characteristics and the construction details to be followed, as well as the classification of the types of waterproofing, the auxiliary waterproofing services, and the complementary waterproofing services. Thus, this is the basic standard for designing a waterproofing system for civil construction.

NBR 9574, in turn, establishes the requirements and recommendations related to the execution of waterproofing so that the minimum conditions of protection of the construction against the passage of fluids are met. In other words, it focuses on the concern to carry out the correct waterproofing procedures according to each type, whether rigid or flexible.

In addition, it cites health, safety and user comfort conditions, seeking to guarantee the watertightness of the constructive parts. The standard applies to all buildings in general, whether they are constructions under construction or buildings subject to expansion and reconstruction - as well as buildings undergoing renovations or repairs.

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Main pathological manifestations of poor waterproofing

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Moisture seeping into the structure is the main cause of various pathological manifestations, especially when it comes to reinforced concrete. The main problems caused by the presence of water in the building elements are:

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Stains and bubbles on the paint

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The main signs of problems caused by seepage and moisture in the paint are the appearance of bubbles, stains, and paint peeling. Although these problems are easily solved with peeling and repainting, they tend to be very aesthetically unpleasant situations, in addition to indicating the possibility of more serious pathological manifestations due to the presence of moisture in the construction.

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Detachment of floors and tiles

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The presence of water in the building structure also has negative impacts on coatings with the detachment of ceramic pieces from floors and tiles. Moisture causes the loss of adhesion of the adhesive mortar of the pieces, causing them to peel off and become subject to fragmentation and falls. As in the case of painting, this is an important sign that there may be deeper problems in the structure.

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Mold or mildew growth

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Also known as mold, mold refers to some species of fungus that grow in humid places, spreading easily in structures that rely on the presence of water. Its presence is very common in buildings with infiltration, especially in places that have little contact with sunlight. In addition to causing stains and damaging surfaces, mold can be a health hazard for building occupants and is responsible for causing respiratory and allergic problems.

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Damage to furniture and objects

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When moisture spreads across the floor or walls, it can spread through the interior of the rooms and even reach the furniture and objects installed in the space. When in constant contact with the presence of water, wood and MDF pieces end up rotting and ruining, for example, while the upholstery suffers from stains and the deterioration of the foam and fabrics. In addition, the presence of moisture also facilitates the development of mold in these items, which can accelerate degradation and cause even more damage.

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Carbonation and armor corrosion

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Carbonation is the process that occurs when there is the presence of water inside the reinforced concrete structure. When air penetrates the pores of the concrete, or even through the spaces caused by the leaching process, if there is moisture, the CO2 present in the atmosphere reacts with the hydroxides present in the concrete. The result is the formation of carbonates, which causes a decrease in the concrete's pH and leaves the reinforcements more exposed, weakening the structure in general.

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Fissures or cracks

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Water seeping into the structure can also cause cracks and cracks to appear in buildings, which indicate more serious problems behind the cracks. In this case, they become even more dangerous, as they can facilitate the passage of moisture and accelerate the deterioration of the building. Therefore, they should not be ignored.

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Efflorescence and concrete leaching

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Efflorescences are pathological manifestations that occur when water penetrates through the concrete and hits the steel reinforcement. Concrete is an alkaline material and, after the cement reacts with water during the curing process, various salts are formed — which, when in contact with moisture, react with water and cause damage to the reinforcement and stability of the concrete. This damage is indicated by the appearance of efflorescences, usually white in color, which appear on the surface of the structure. This problem is very common in places where water exerts pressure against concrete, penetrating through the pores.

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Examples of waterproofing materials available on the market

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Waterproofing rigid waterproofing systems are specific mortars or additives for mortars and concrete that reduce porosity, providing greater waterproofness.

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Rigid waterproofing agents

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Rigid waterproofing boils down to specific mortars or mortar additives that decrease porosity. By reducing the voids between the substrates of the mixture, the final product has lower permeability and is able to prevent moisture from passing through. The main types of rigid waterproofing are:

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Waterproof mortar - water-repellent additives

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The waterproof mortar is nothing more than a traditional cement mortar with the application of waterproofing agents to the mixture — in this case, the water-repellent additives. It has a very competitive price and is easy to execute. As a rigid waterproofing system, it is suitable for application in buried places, retaining walls, elevator shafts, and areas with low thermal movement in general, such as baldrame beams and floors in contact with the ground.

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Polymer mortar

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Polymeric mortar is a mixture of cement, minerals or aggregates, and acrylic polymer additives, forming an impermeable coating with high resistance that clogs the pores of the material to be protected. It is cost-effective and is suitable for application in underground reservoirs, basements, elevator shafts, retaining walls, baldrame beams, swimming pools and internal walls, as well as cold floors, as well as in kitchen and bathroom areas. It needs a finish in the form of a coating to ensure the mechanical protection of the waterproofing agent.

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Crystallizing cements

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In the same way, crystallizers are waterproofing substances that are added to the concrete mix. This additive guarantees the waterproofing of concrete through the formation of insoluble crystals in the capillaries, which expand when in contact with moisture. In this way, they seal the pores of the concrete and prevent the passage of water, and are suitable for foundations, pools, tunnels and underground slabs, among others.

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Flexible waterproofing agents

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Flexible waterproofing agents generally act as a protective membrane, thus preventing water infiltration. They can be applied alone or with the reinforcement of tensile resistant materials. The main types of flexible waterproofing are:

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Asphalt and polymer membranes

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Membranes are waterproofing layers molded on site, which may be asphalt or polymeric (elastomeric, with the use of neoprene or hypalon, or acrylic). Some examples are polyurea, which has good durability, elasticity and mechanical resistance and is suitable for very aggressive environments, and acrylic emulsion, an emulsion of thermoplastic acrylic compounds with water used in areas that are difficult to access, but not suitable for areas with human and vehicle traffic.

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Asphalt and polymer blankets

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The blankets are prefabricated products, which arrive ready for assembly in the place to be waterproofed. Asphalt is one of the most used waterproofing systems in Brazil, and can also be polymeric (elastomeric, with EPDM or butyl, or plastic, with the addition of PVC or HDPE).

This type of product is suitable for areas with large movements, such as slabs, reservoirs, gardens, gutters and cold areas in general. However, it needs coating to ensure mechanical protection and prevent damage to the blanket.

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Discover Blok's waterproofing agents

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Blok has the best waterproofing products, developed with the highest performance technologies to ensure the efficiency of your work. Here are some of our waterproofing options for you to explore:

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Blok EP line

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Blok EP is a flexible waterproofing coating for negative hydrostatic pressures, formulated from mineral additives, rheological modifiers and acrylic resins with excellent waterproofing properties, flexibility and adhesion. Highly recommended for retaining walls, drinking water reservoirs, swimming pools, floors and walls in cold areas such as bathrooms, kitchens and service areas, balconies and foundations, places with rain and plastering. It also includes Blok EP 2, a product with wide application suitable for baldrames and foundations, places with rain, plasters, planters and flower boxes.

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Blok RF line

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Blok RF is a flexible waterproofing coating for positive hydrostatic pressures, suitable for slabs, terraces, balconies, retaining walls, drinking water reservoirs, swimming pools, floors, walls, wetable areas, baldrames and foundations, plasters and places with rain. It also has Blok RSF, the semi-flexible version of the product.

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Blok ST

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Blok ST is a flexible waterproofing coating for structured flexible polymer mortar, highly recommended for sealing and eliminating leaks and strongly combating moisture, such as in wetted areas, slabs, pools, baldrame, foundations, water tanks and reservoirs. Along the same lines, we have the Blok ST2, the semi-flexible version of the product, and the Blok STP and STP2, ideal for flexible polymer mortar structured for negative pressure, in a flexible and semi-flexible version.

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Blok Massa

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BlokMassa is a waterproofing additive for plastering, and leveling that assists in waterproofing by blocking the capillary system, allowing gas exchange between materials. It is highly recommended for plastering, laying, and leveling concrete and mortars.

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BlokTume

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BlockTume is an ultra-resistant asphalt waterproofing paint composed of a high concentration of diluted asphalt, which guarantees excellent coverage when applied to the surface. It is ideal for applications on baldrames, foundations, restraints, metal structures not exposed to the elements, wooden structures not exposed to the elements, adhesion bridge for applying asphalt blankets, primer for applying blankets and self-adhesive tapes. It is a monocomponent with high adhesion, chemical resistance, covering power, waterproof and quick-drying.

In the same line, we also have other products. BlockTume Frio is an ultra-resistant water-based asphalt waterproofing emulsion for applications on baldrames, foundations, restraints, metal structures not exposed to the elements, wooden structures not exposed to the elements, adhesion bridge for applying asphalt blankets, primer for applying blankets and self-adhesive tapes.

BlockTume Flex is an ultra-resistant elastomeric waterproofing asphalt paint composed of a high concentration of diluted asphalt, which guarantees excellent coverage when applied to the surface. It guarantees a perfect seam between asphalt blankets and waterproofing of surfaces such as slabs, bathrooms, balconies, kitchens, service areas, foundations, baldrames, retaining walls, drywall and concrete surfaces in general. Finally, the BlockTume Flex AC is the water-based version of this product.

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BlokSeal Floors

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BlokSeal Floors is a high-performance water repellent that, when applied to floors, creates an invisible layer of protection that prevents water infiltration.

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BlokGesso

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BlokGesso seeks to promote water resistance and increase the durability of the material when exposed to moisture. In addition to its very high performance, BlokGesso is a water repellent for plaster that guarantees performance incomparable to any other product, protecting not only the surface, but the entire plaster mass. Ideal for the production of decorative pieces, drywall sheets, hydro plaster blocks, GRGH, moldings, moldings, 3D plaster plates, plaster artifacts in general and even for crafts.

Blok is always committed to delivering the best products for your work. Visit our website and discover all our waterproofing solutions!