Waterproofing And Sealing Of Cracks, Brick, And Other Bases

Table of Contents

• Reasons for cracks formation
• Classification and types of cracks
• Features of crack waterproofing
• Methods of waterproofing cracks and materials used for repair
  • Injection of cracks in concrete
    • How crack injection is performed:
• The cost of sealing cracks
• Calculator for self-calculation of the cost of injection and stitch waterproofing

The formation of cracks – is a rather bad sign indicating the structural destruction of concrete or other building material. If cracks are detected, you definitely need to take action. In order to take adequate and effective measures, you need to understand the causes of these destructions.

Reasons for cracks formation

Cracks in a house, building, basement, foundation, or on walls can be formed for several reasons:

1. Dynamics of the substrate from the ground under the foundation of the building. If the foundation of the building is made incorrectly, then in the case of high groundwater, leaching of soil from under the foundation and the dynamics of the soil under it, the foundation may move, as a result of which cracks may appear in the basement walls and in the foundation.
   
   
2. The impact of water on concrete, brick, FBS blocks, or other material from which the walls or foundation of the house are made. If there is no high-quality waterproofing of the foundation and basement walls or socle outside the underground part of the building, then the top and the groundwater can be absorbed into the concrete or other foundation, since concrete and most other materials are a sponge for water.
   
   When water is absorbed into the foundations, it freezes in winter and thaws in spring, which leads to the gradual destruction of concrete and other materials, and the formation of pores, voids, and microcracks. The resulting microcracks increase every year and can subsequently turn into a serious crack through which water can get inside the room. 
   
3. Low-quality concrete.
   
4. Construction without taking into account loads or with incorrect calculations.
   
5. Incorrect approach to the installation of cold and deformation seams.
   
6. Incorrect calculation of the reinforcement and performance of work related to the reinforcement of the structure.

Important: If you find a crack in your basement or in the walls of your house, you need to take action immediately. With each passing day, the resulting crack can increase and lead to a thorough destruction. The time of destruction and growth of the cracks formed depends on the quality of the poured concrete during construction.

Classification and types of cracks

Types of cracks due to their formation:

1. Shrinkage– Formed as a result of an incorrectly selected composition during the preparation of concrete, for example, a large consumption of cement. They also may appear when the hardening process is disrupted or the wrong method of concrete caring is chosen during its hardening. Sometimes shrinkage cracks appear as a result of improper reinforcement.
2. Temperature – caused by temperature fluctuations, improper processing and retention period in the manufacture of concrete. These cracks are also formed during operation as a result of the destructive actions of frozen and then thawed water inside the concrete.
3. Sedimentary cracks – Formed as a result of the dynamics of the supports or foundation slab.
4. Deformation – The appearance of cracks is caused by improper storage, transportation, installation of concrete or its operation. They are formed due to poor concrete, incorrect calculation of loads or reinforcement.

Types of cracks by their nature and direction:

1. Stable
2. Unstabilized
3. End-to-end
4. Single-sided
5. Longitudinal
6. Horizontal 
7. Transverse
8. Vertical
9. Single
10. Parallel
11. Intersecting

Types of cracks by the size of their depth:

1. Hair – up to 0.1mm
2. Small – up to 0.3mm
3. Developed – up to 0.3mm-0.5mm
4. Large – up to 0.6mm and more

Below is a detailed classification scheme for cracks in structures with the definition of all types and the degree of their danger for further operation of the structure:

Features of crack waterproofing

If a crack in a wall or other place was formed due to the lack of high-quality waterproofing, statistical water-pressure or as a result of its freezing and thawing in the base, then you need to seal it. Waterproofing or sealing of cracks should also be performed if water passes through the formed crack or moisture appears.

In order to choose the right technology and method of waterproofing and sealing cracks, you should first understand what is the reason of their formation. The method of which waterproofing will be formed directly depends on the nature and type of crack. 

In order to properly approach the issue of sealing, it is necessary to call a qualified engineer from a large and professional company whose specialization is waterproofing to inspect your problem.

Important: If water passes through the formed crack, then the external waterproofing of your house, structure or building is broken. If possible, in addition to sealing the problem area from the inside, it is recommended to make a good external waterproofing of the underground parts of the building, so that later water could not come into contact with concrete and destroy it.

Methods of waterproofing cracks and materials used for repair

If a crack has formed due to the impact of water, then it should be sealed. Otherwise, the crack is likely to continue to collapse and grow under the influence of the same moisture and water.

The main methods and technologies of sealing formed cracks:

1. Layer-by-layer sealing of special sealants – the crack is previously expanded, then a special sealant is layer-by-layer sealed into the formed cavity, the task of which is to bind the damaged areas and prevent water from entering the room.
2. Injection waterproofing – is the most effective way of sealing. Polyurethane resin or other hydrophobic composition is supplied under pressure to the problem area with the help of special equipment, thereby filling all voids and cavities.
3. Cementation – Micro-cements are applied under pressure instead of forming a crack, thereby binding and strengthening it. This method is mainly used for problems associated with strengthening the foundation or with the formation of cracks above ground level, for reasons unrelated to water.

Basic materials for sealing, protecting and waterproofing cracks:

1. Expanding sealants – When moisture enters, these sealants tend to expand or swell.
2. Hydro seal – designed to stop active water leaks.
3. Swelling cords – Swell when moisture enters, forming a barrier to water. These cords are usually used in waterproofing seams.
4. Polyurethane resin – is injected into the concrete, blocks, bricks and other substances using pressure created by special injection equipment. There are a number of injection resins and foaming agents for sealing, from single-component urethane solutions to multicomponent systems.
   
   Choosing the right composition depends on the application and the presence or absence of humidity. Some injectable materials need water to react, while others do not react if moisture is present. When injecting, it is almost always recommended to introduce polyurethane compositions over epoxy resins, because they remain permanently elastic and bind well to the base. Helium injection resin –is suitable for injecting those places where there is a lot of dynamics and there is a possibility that the polyurethane resin will crack over time.

Important: The most effective method for eliminating leaks and sealing all types of cracks — is an injection method of waterproofing. When performing injection work, the waterproofing compound is supplied under pressure, so that it penetrates into all possible voids and microcracks in concrete to their entire depth, which cannot be done with manual sealing of the sealant.

Injection of cracks in concrete

Injection of cracks is possible both in the concrete base and in the brickwork. To eliminate leaks and cracks from the inside, it is best to use injection waterproofing. Its meaning is that polyurethane resins or gels, under pressure, penetrate into all voids of a concrete or brick structure, squeezing out all moisture from there, filling them and making the surface more waterproof and resistant to moisture.

How crack injection is performed:

1. If we are talking about sealing cracks, cold seams, junctions and joints of the wall slab, then first it is important to stitch these places, making a   swallow-shaped indenting, and then seal the expanding repair mixture there according to the type of HydroExpand. This procedure is carried out so that the injection resin gets exactly where it needs to be when injected and does not go out through weak cold seams, cracks or joints.
2. Then, small wells are drilled along the perimeter of the crack. If we are talking about a crack, then the holes are drilled staggered from opposite sides at an angle of 45° to the center of the crack. Since the course of the crack below the surface is unknown, this procedure ensures that at least every second well crosses the crack.
3. Special metal ports or packers are installed in the wells.
4. Polyurethane resin is sprayed or injected into wells using a high-pressure injection pump, through special valves called injection ports, which are installed in wells (holes).
5. The injection ports through which the injection was carried out are removed, and the holes are sealed with a special sealant.

The cost of sealing cracks

Description of work	Unit of measurement	Price in roubles
Work on the expansion of the crack by the method of the installation of indenting with its further clearing	running meter	10
Layer-by-layer sealing of the Expanding sealant	running meter	14
Injection waterproofing of cracks: -Work on the installation of boreholes and assembly of packers -a complex of works on injection -dismantling of packers and sealing of injection holes	running meter	50
Injection waterproofing into the concrete body   -marking, Work on the installation of boreholes and assembly of packers -a complex of works on injection -dismantling of packers and sealing of injection holes	m2	70
Injection waterproofing into the brick body -marking, Work on the installation of boreholes and assembly of packers -a complex of works on injection -dismantling of packers and sealing of injection holes	m2	70
Polymer-cement waterproofing	m2	10
Waterproofing of the communications entry points: -Work on the installation of indenting -clearing the indenting -layer-by-layer sealing of non-shrinkable composition – Work on the installation of boreholes and assembly of packers -a complex of works on injection -dismantling of packers and sealing of injection holes	piece	140

Calculator for self-calculation of the cost of injection and stitch waterproofing