Did you know that waterproofing a foundation is one of the most important steps in any project?
Foundation beams are one of the most common types of foundations in civil construction, used on a large scale for the construction of small buildings - such as houses and low-rise buildings. It is a simple structure, executed in concrete or mortar stone, capable of withstanding small loads with efficiency and low cost. However, as it is a structure that is in direct contact with the ground, it is permanently exposed to the moisture present in the earth.
In turn, water infiltration into the structure is one of the biggest problems faced by buildings, and moisture can penetrate the building in various ways: through roof problems, leaks in the building's hydrosanitary system, or rising from the ground through the foundation. In this sense, foundation waterproofing acts as a protective barrier, which prevents the moisture that comes from the soil from entering the foundation and passing to the other elements of the structure, creating pathologies that can create inconveniences and damage the construction, reducing its useful life.
Therefore, it is important to ensure the efficiency of this protective barrier right at the time of construction. In this article, we will better understand what foundation waterproofing is and the importance of ensuring good waterproofing for your work, in addition to learning how to perform quality foundation waterproofing. Check out the following:
The importance of good foundation waterproofing
As the materials used in the construction of foundation beams are not waterproof, they are not able to prevent moisture from passing from the soil through the pores of the structure, reaching the top of the foundation and passing on to the other elements of the building, such as floors and walls. Thus, it is essential to carry out a good waterproofing of the foundation, isolating the moisture coming from the ground and preventing the passage of water to the upper parts of the structure - where the infiltration can cause great damage, as we will see later in the text.
In addition, since it is a buried element, maintaining or repairing foundation beams is extremely difficult and sometimes even unfeasible. Thus, it is essential to also guarantee the quality of the waterproofing performed on this structure at the time of construction, avoiding rework and future expenses to correct the waterproofing problems and the pathologies caused by the presence of moisture in the building elements.
On average, the cost to waterproof a building represents 1% to 2% of the construction cost. On the other hand, the expenses and inconvenience to correct the problems caused by the lack of waterproofing are much higher. As the popular saying goes, prevention is better than cure, isn't it? Next, let's look at the consequences of inefficient building waterproofing.
Main problems of poor waterproofing
The lack of foundation waterproofing or the execution of poor quality waterproofing can cause various pathologies in the building. The main ones are:
Appearance of mold or mildew
Mold, also known as mildew, is the name commonly given to some species of fungus that grow in humid places. It spreads easily in structures that rely on the presence of water, especially when they have little contact with sunlight. Thus, they are very common in buildings with infiltration, causing stains and may cause health problems, especially respiratory and allergic diseases.
When moisture spreads across the floor or walls, mold can even reach the furniture installed in the room. Wood and MDF parts, when in contact with moisture, end up rotting and ruining, while upholstery suffers from stains and the deterioration of the foam and fabrics.
Carbonation and corrosion of concrete
When air penetrates the pores of the concrete, or even through the spaces caused by the leaching process, in an environment with the presence of water, the CO2 present in the atmosphere reacts with the hydroxides present in the concrete. This causes the formation of carbonates and causes a decrease in the concrete's pH, which leaves the reinforcements more exposed and weakens the structure.
Painting problems
Blisters, stains, and peeling paint are some of the most common problems evident in painting caused by seepage and moisture. Although they ruin the aesthetics of the environment, they are easy problems to be solved with peeling and repainting - but they usually indicate the possibility of more serious pathologies due to the presence of moisture in the construction.
Detachment of floors and tiles
As in the case of painting, the presence of water in the building structure has effects on the coatings with the detachment of the ceramic pieces from the floors and tiles. Likewise, the loss of adhesion of the adhesive mortar of the parts due to moisture is a sign of deeper problems in the structure.
Fissures or cracks
Infiltration can also cause cracks and cracks to appear in buildings. In this case, they become even more dangerous, since in addition to exposing structural problems, they can facilitate the passage of moisture and accelerate the deterioration of the building.
Efflorescence and concrete leaching
Efflorescences are very common pathologies in places where water exerts pressure against concrete, penetrating through the pores and reaching the steel reinforcement. Concrete is an alkaline material, and after the cement reacts with water during the curing process, various salts are formed. When water penetrates the pores of the concrete, these salts react with moisture and cause damage to the reinforcement and stability of the concrete, indicated by the appearance of efflorescence, usually white in color.
Step by step on how to perform foundation waterproofing
The execution of a foundation waterproofing is not normally a complex or very expensive process, but there are some precautions that must be respected to ensure its efficiency against the passage of water in the future. The technical standards of ABNT NBR 9574: Execution of waterproofing — Procedure and NBR 9575: Waterproofing — Selection and design are the main guides when it comes to this issue, providing the regulations used to ensure the correct execution of the waterproofing.
Step 1: preliminary study
The first step in doing a good foundation waterproofing is to define the type of waterproofing that will be performed. This choice must take into account several factors, such as the type of element to be protected, the level of aggressiveness and exposure.
Although products such as asphalt blankets can be used, the solution most traditionally used to waterproof foundation beams combines the application of waterproof mortar and asphalt paint, mainly because they are easy to apply and have a competitive cost.
Step 2: cleaning the structure
To ensure the quality of the execution of your foundation waterproofing, you need to make sure that the structure is clean and ready to receive the waterproofing products. Thus, ensure that the beams are free of impurities such as dust and dirt, as well as sanitized from potential mold release residues and remains of the forms.
Then, so that the beam is prepared to receive the mortar, it is important to moisten the surfaces with a brush and apply a layer of chapisco. It will serve as an adhesion bridge for the mortar.
Step 3: applying the waterproof mortar
The waterproof mortar must be prepared with a waterproofing additive, and follow all the supplier's indications regarding the trace and additional care to be efficient, such as the thickness of the mortar, the number of layers to be applied, the finish and the curing time.
Step 4: applying the waterproofing agent
Finally, the last step in waterproofing foundation is the application of polymer mortar. It is recommended to use at least three coats and that, as with regard to the materials and additives used in the waterproof mortar, that quality products be chosen to guarantee moisture protection in the structure.
Blok is a brand with experience in the development of construction products, with certified quality in the market. Visit our site to learn more about waterproofing structures and learn about our waterproofing solutions for your work! Leave your questions in the comments below, or contact our team — we're ready to help. We are waiting for you!
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