Table of Contents
Vertical Vs Horizontal Foundation Cracks
Whenever a house starts getting older, many major faults and drawbacks can be witnessed, which may be detrimental to the house in the longer tend analyses of the foundation.
They also suggest if it requires repair as soon as possible or should the replacement of the foundation be done.
If that particular foundation can attain its previous strength through repair, which repair method should be suitable for that type of foundation?
The type of repair depends upon various factors; soil characteristics are one of them. The foundation experts suggest the repair method depending upon those factors.
A Guide to Vertical Vs Horizontal Foundation Cracks
The structure can be of different types, as well, and the cracks that appear on them can be of various types. Depending upon the type of cracks that appeared on the structure, they can be mainly divided into two subcategories, they are:
Type of Cracks That Appeared on the Structure
There can be various types of appearance on the structures; they are as follows:
1. Cracks between the slab and Masonry wall
Whenever a Masonry wall connects the slab, cracks can be formed between them. The reason for that can be said as thermal expansion. Concrete has a different thermal expansion than the Masonry wall.
So In the presence of heat, concrete expands more as compared to a Masonry wall. Thus horizontal cracks may be formed at the joint of the Reinforced concrete slab and Masonry wall.
2. Cracks Between the Column and Masonry Wall
Similar to that of the concrete slab and Masonry wall, vertical cracks may be formed between Vertical columns and Masonry wall. The reasons for this type of crack are similar to that of the previous one.
The thermal expansion for concrete and Masonry walls, which are mainly built with bricks and mortar, are different. Thus in an open atmosphere, the concrete expands more than the Masonry wall.
As Masonry walls and columns are already jointed and are a rigid structure, stresses may be formed between them, which results in vertical cracks as well.
3. Cracks due to Chemical Reactions
This type of crack is dependent upon the Climatic condition of that particular region, as well as soil condition and its characteristics. However, this type of crack is very prone to building foundations but can be seen in other structures as well.
Many a time, in the seaside region, the soil is of very poor quality, and the sulfate content is higher than the ordinary soil.
Due to this high sulfate content, adverse effects on the foundation as well as on the walls can be seen. These adverse effects particularly include severe cracks and efflorescence as well.
4. Cracks in Foundation
This is particularly the portion that we will discuss more in upcoming sections. Cracks in foundations can be the most detrimental among all types of cracks.
The reason may be included in the following:
Causes of Foundation Cracks
The causes of foundation cracks are generally included in the following sections:
Many a time, it happens that the design proposed for that foundation, Includes several errors and mistakes. In that case, the probability of the failure of the foundation is very high.
As the strength of all structural components primarily depends upon the design criterion, the wrong design may result in the complete failure of the foundation.
This design should be made very accurately for the foundation, and it should be approved by government officials. If necessary, foundation experts must be hired to suggest appropriate ways to build the foundation, and the work should only be given to reliable and well-known contractors.
Uneven Settlement of Soil
Whenever a house is built, the characteristics and properties of the soil might change with time. Along with that, the level of the groundwater table may also change with time.
As the groundwater table increases, the soil becomes more and more permeable, thus of inferior quality. As soil condition falls, the safe bearing capacity estimated earlier before building the foundation also falls.
Thus due to poor bearing capacity, the subsoil becomes unable to carry the loads transferred from the structure to the foundation. Thus, as a result, the foundation fails severely.
To prevent that, care should be taken to periodically conduct soil investigations by local testing agencies and also to conduct investigations on the conditions of the foundation.
Inadequate Mix Design of concrete
Due to the preliminary mix design of concrete, cracks may be formed on the surface of the concrete as well. Many a time, it happens that a mixed design of concrete, which should be poured into the foundation, becomes inadequate and thus does not attains its design strength.
As the foundation is the most important structure of the building, which practically carries all the loads, including dead and live loads coming from the slab, inadequate design strength may result in the severe failure of the foundation.
Growth of Roots of Trees
Many a time, while constructing a building, many trees are cut from below. But the roots of the trees, most of the time, are left out from cutting.
As the roots are left out, in the presence of adequate Climatic conditions and water content(which the roots adequately receive from the groundwater table), it starts to grow again.
After the passing of several years, the strength of the foundation also decreases, and along with that, the roots of the trees start coming beneath the foundation.
As soon as it reaches the foundation’s bottom, it starts to press the foundation, as the foundation becomes an obstruction to its growth of it.
As the strength of the foundation also decreased throughout the years due to pressure from the root of trees, it became unable to bear the stress, and cracks appeared on the side as well as on the top surface of the foundation.
Although it can not affect the foundation in a short time, it can severely affect the foundation over a long time.
Types of Foundation Cracks depending upon its Materials
Foundation may be constructed using two types of materials; they are, Concrete and bricks. Thus the cracks appearing on them are completely dependent upon these two types of materials as well. Some of the types of cracks depending upon their materials, are given below:
Concrete Foundation Cracks:
Nowadays, concretes are constructed using concrete as a major material. Various types of cracks may form over the surface of the concrete; some of them are explained in the following:
1. Plastic Shrinkage Cracks
Whenever concrete is poured into the Reinforcement caging of the foundation, in the presence of sunlight and an open atmosphere, the water content present in the concrete starts to dry. As a result of the continuous evaporation of water, large voids may form between the aggregates of concrete.
This happens as soon as the concrete is poured; that is, when the concrete remains in the plastic state. As voids are formed between the Aggregates, the formation of cracks are noticed at the top surface of the foundation.
Although it comes under the category of fine cracks(cracks having a width less than 5 millimeters) and is mostly present in all concrete structures, it should not be allowed to propagate. Plastic Shrinkage Cracks are generally formed throughout the foundation.
Drying Shrinkage Cracks: After the concrete becomes completely dry and attains its stipulated strength in the required time, it is called hardened concrete.
Forming of cracks can also be seen in hardened concrete as well. These types of cracks are termed drying Shrinkage Cracks.
The concept behind the formation of these types of cracks in the internal voids is present inside the concrete.
Due to vibration, most of the air voids get depleted, but a little of them remain inside the concrete, which over time, starts to shrink. Thus drying Shrinkage Cracks occur.
Similar to plastic Shrinkage Cracks, drying Shrinkage Cracks come under the category of fine cracks as well and is not much detrimental to the concrete structure.
2. Expansion Concrete Cracks
Whenever the depth of the concrete is very thin and is placed in direct sunlight and an open atmosphere(particularly happens in the case of Pavement Quality Concrete for the building of pavement), the water rapidly evaporates from the surface.
Thus one type of crack that is very common to this type of Concrete is a plastic Shrinkage Crack, as explained earlier. As concrete is placed directly over sunlight, there is a high probability of concrete expansion in this case.
As concrete shows the tendency to expand, if any obstruction is found along its length or its width, it pushes the obstruction. Due to the outward thrust, high-stress forms within the concrete as well.
Due to this stress, concrete cracks occur along its length or its width. This type of crack is termed an expansion crack. To prevent this, care should be taken to leave a minimized number of expansion gaps along its length.
3. Heaving Concrete Cracks
Whenever concrete is poured in the Colder region, it is subjected to frost action. Due to the frost action, the concrete for that particular portion(especially for pavements), and its surrounding portion freezes.
After the temperature rises, the concrete surface melts, which is again followed by freezing in a cold climate. This cycle is termed the Freezing and thawing cycle, and thus, a huge factor contributing to the cracks in concrete.
Whenever a particular concrete surface melts, Having the surrounding portion in freezing condition, high stress is formed in concrete due to temperature variation.
Due to that high stress, the heaving of concrete occurs, resulting in forming of cracks. This type of crack is termed heaving concrete cracks and is very much detrimental to the concrete.
4. Settling Concrete Cracks
Due to the change in soil characteristics and also the groundwater table level, settlement of the Concrete Foundation can be noticed due to the low bearing capacity of the soil.
As the foundation is a rigid structure, whenever it settles due to the soil settlement, cracks can be formed vertically as well as horizontally on the foundation surface.
Many a time, major vertical cracks can be noticed in the concrete foundation, which is excessively detrimental to the structure itself.
Thus utmost care should be taken to ensure proper repairing of cracks if they appear on the concrete surface and to implement Preventive measures before the appearance of the cracks.
Concrete Cracks due to overloading of Slab: Due to the high overloading of the slab, cracks can appear on the surface of the slab as well as on the surface of the foundation as well, due to being under high stress.
Masonry Foundation Cracks
Nowadays, Masonry foundations are extinct as compared to concrete foundations. But there are many places where erecting Masonry foundations is still in use.
Masonry foundation is a very economical and low-cost solution for building any foundation, although it is not that conventional and does not provide the required strength as compared to concrete. Some types of cracks which can be formed over Masonry Foundation are as below:
1. As a Masonry Foundation is primarily built on bricks and mortar, failure of a masonry foundation means the failure of its construction material, that is, bricks and mortars. The main reason for masonry foundation cracking is the groundwater table.
As bricks can absorb water to a great extent, it affects the strength of the masonry foundation as well. A brick is termed as good when it absorbs water up to 20 percent.
If the bricks used for building the foundation are not that good (which have a water absorption percentage of more than 20 percent), and if the groundwater table is at a lower depth from the foundation, the bricks start to rapidly absorb water from the soil.
In the presence of high water content, the strength of the bricks falls rapidly, thus failing the foundation as a whole.
2. Many a time, chemical reactions may take place between the constituents of bricks and soil ingredients.
As an example, if the presence of sulfate is very high on a particular soil due to the chemical reaction, a high amount of efflorescence may be found on the surface of the bricks, which adversely results in a fall of strength as well.
Thus due to the chemical reaction, cracks may appear on the surface of the bricks.
Vertical Cracks Vs Horizontal Cracks
Although both come under the category of structural cracks, there can be a wide difference between Vertical and horizontal cracks formed in the foundation. Some of them are as follows:
- The formation of horizontal cracks can happen on the surface of the concrete, which particularly depends upon the concrete mix proportion, placing techniques, and the weather in which the concrete has been placed. Some example of these types of cracks has already been explained earlier, such as plastic Shrinkage Cracks, drying Shrinkage Cracks, and expansion Concrete Cracks. On the other hand, vertical cracks formed generally depend upon the soil characteristics and properties, soil safe bearing strength, and the effect of the groundwater table, which is particularly responsible for the settlement of the soil as well as the settlement of the foundation as well.
- Horizontal cracks formed generally comes under the category of fine cracks, which have a width of less than 5mm, and it very narrow. Horizontal cracks are not generally much detrimental to the foundation and exist in almost all concrete foundations. On the other hand, Vertical cracks formed generally comes under the category of extensive danger cracks(which have a width of 15-20 millimeters) and are very much detrimental to the structure itself.
- As horizontal cracks are not detrimental to the structure, it does not propagate through the foundation as well. On the other hand, Vertical cracks propagate rapidly, and if left untreated, they may fail the structure itself.
Deciding Methods Whether You Need to Repair
Whenever a crack appears on the foundation, there are two ways available first, to repair the cracks and second, to replace the foundation.
Deciding between these two methods can be quite a task. While deciding, several factors should be kept in mind, upon which the decision completely depends. The factors are as follows:
- Length of the crack
- Width of the crack(whether it comes under the category of fine cracks or in the category of extensive danger type)
- If the crack is spread throughout the foundation or spread in a particular region
- Whether it is a horizontal or vertical crack;
- Whether access is available for repairing the crack;
Depending upon the following factors, the decision is taken if repair is to be done or complete replacement of foundation is to be adopted(Generally known as Undermining)
Repair Methods of Foundation Cracks
This is the most commonly adopted procedure for treating cracks. Some reasons why it is adopted mostly as compared to the complete replacement of the foundation are as follows:
- This is the most conventional method for treating cracks, as many of the local agencies are available for the sole purpose of doing that.
- The repair method provides a low-cost solution with possible resources as compared to undermining, which involves high costs as well as additional resources.
- Foundation repair methods consume less time as compared to undermining or complete replacement of the foundation, which consumes a large amount of time as well.
Some popular repair methods of Foundation repair are mentioned as follows:
Grouting Method of Repairing
This is by far the most common method for treating the fine to extensive danger category of cracks. This method involves PVC nozzles through which the grout should be applied, a suitable grouting material for crack repairing purposes which may be Cement slurry, a mixture of cement and sand, and chemical adhesives.
When chemical adhesives are used, Fosroc Conbextra GP-2 is a popular choice of Grouting Material. These chemical adhesives come with packaging of 20-25kg and can be provided barely or using a mixture of cement, sand, and Grouting Material.
Portland cement Grouting is another process of Grouting as well, but in this case, controlled quality of water should be given to minimize Shrinkage and achieve its optimal strength.
In this type of Grouting, the surface is cleaned up with any undesirable substances using the brush. Then a grout mesh is provided. The grout mesh is intended for the proper application of Grouting Material and to minimize wastage as well.
The interval of installation of grout mesh should be consulted with the grouting agency or with a foundation repairing professional. After applying the grout mesh, grout Material is to be applied over it.
Finally, a layer of cement slurry is applied over it, and if required, a render coat of plaster(Having a thickness of 3-5 millimeters) is applied over the repaired surface.
- Using Epoxy Injection: This is another conventional of repairing concrete surfaces as well. In the case of the Epoxy injection procedure, PVC nozzles are fixed over the total length of the surface. The numbers and the interval of these nozzles are suggested by the repairing agency or by any foundation repair expert. After that, Epoxy is applied over it, which with time, hardens and retains its full strength.
- Routing and Sealing: This is a much more common as well as a simpler method of crack repairing. Although this type of repairing is adopted for fine cracks also does not pose a serious threat to the foundation and does not involve the restoration of the complete tensile strength of the foundation. In this method, a V-shaped groove is first cut throughout the length of the crack. After that, the surface of the groove is cleaned with a brush. Following that, sealants or sealing agents are applied over the groove, which with time, hardens and gains its stipulated strength.
- Stitching the cracks: Although this is one of the uncommon methods of repairing foundation cracks, in many European countries, this type of repairing system is adopted particularly for pavements. In this type of repair system, at first, several holes are drilled along the length of the crack on both sides. After drilling, the crack is then tied using a binding wire. The binding wire chosen should be as per the required specifications, which prevents the propagation of the cracks further, thus resisting the outward thrust of the concrete as well.
- Drilling & Plugging: This is a very cost-effective solution and a good repair method for vertical cracks, which run in straight lines. In this method, a drill is holed on the crack, over which a key is then formed by passing a grout. Further, the remaining portion can be repaired by surface treatments from solution, dry packing, and gravity filling as well. The key formed by passing down a grout resists the propagation of cracks. This method is less time-consuming as well.
- Dry Packing: This method is adopted for minor surface cracks. In this method, low water content mortar is hand placed in the cracks, which is then followed by ramming or tamping the surface to even it. In this method, care should be taken to only use low water content mortar so that the mix remains tight and has less Shrinkage as well as to attain its optimal strength.
Where to Find Foundation Repair Professionals
While a crack appears on the surface, the best way to deal with it is to hire a foundation expert or foundation professional. There are particularly three ways through which one can hire foundation experts:
1. Through Local Agencies
Along with the cup-gradation of technology, nowadays, foundation experts can be hired to inspect the foundation of a house beforehand. There are many local agencies as well as foundation repair agencies available, which provide consultation from foundation professionals.
One needs to book an appointment, and then the foundation expert visits the house, conducts the required testing, and suggests a better way to treat the crack on the foundation. Hiring foundation experts from local agencies is the most popular nowadays, which is cost-effective as well.
As technology upgraded, the process of hiring foundation professionals widened from local agencies and local contracting agencies for foundation repair to the online market as well. At the current time, there are several websites available where freelancing foundation professionals can be found.
The benefit of hiring freelancers through a freelancing site is that it provides a low-cost solution as compared to local agencies, and the appointment can be arranged fast as well. Thus it is a very economical approach to consult any foundation expert for foundation repair.
3. Using Resources
Many a time, it happens that you know a foundation expert, or you have some friend who has hired a foundation expert for consultation and knows them very well. Thus using personal resources, one can hire a foundation expert as well. The benefit of hiring foundation professionals in this way has its advantages.
The best advantage is you can review that foundation professional through your friend you know, thus making sure he provides the most cost-effective and reliable technical solution. On the other hand, hiring through known resources can save a lot of money from hiring unknown foundation experts who do not serve you the best technical solution.
Cost to Fix Horizontal Cracks in Foundation
The cost to fix horizontal cracks in the foundation depends upon several factors. Some of them are explained below:
- Length of the cracks
- Width of the cracks (whether it comes under the category of fine cracks; or extensive danger type)
- Type of soil, soil characteristics, and groundwater table
- Whether settlement has occurred or not;
- Economic approach.
Depending upon the following factors, different local agencies for foundation repair, and different contracting agencies, charge differently. While considering the cost, labor daily wages, the number of labor to be implemented, material cost, etc are taken into account as well.
1. Cost of Materials
The cost of materials is the primary cost that needs to be incurred in total cost. For foundation repair through the grouting method, the materials required are PVC nozzles which are inserted throughout the cracks(numbers and center-to-center distance of PVC nozzles are to be determined by a repairing expert
by that particular contractor who has been hired for repair); Cement and water(for cementitious grouting) or chemical sealants, epoxy(for injection grouting – Fosroc Conbextra GP2 is a popular Grouting Material nowadays), cost of cement and sand(for render coat plastering if it is required).
For Injection grouting, the price of chemical sealants generally varies from 300₹ to 500₹, which comes in packaging of 20-25kg. The technical specifications of that specific grouting material can be found on the website as well.
2. Cost of Labour
The cost of Labour depends upon the number of laborers deployed(skilled or unskilled) for that purpose and their daily wages. The daily wages of Labour generally vary from 300₹ to 800₹ depending upon how skilled they are.
Generally, 5-6 laborers are deployed maximum to repair work. The more labor used for the repair work, the less time will be taken to complete the work.
3. Agency’s Profit
It depends upon the type of agency that is deployed for that repair work. If that contracting agency is well known and famous, it will incur a low profit as it has many customers.
If that agency is new in this field and does not have much experience regarding it, and also does not have many customers as well, it would be a little high as compared to the well-known agency.
But it is always advisable to hire a well-known contracting agency that has a lot of experience and specializes in this field, as even a little mistake can fail the whole structure this case.
Horizontal Cracks in Foundation Walls
Horizontal cracks can be formed in Foundation walls due to several factors, some of which are explained below:
- Structural Reasons: Cracks may be formed in foundation walls for structural reasons. Whenever a required number of extra bars are not provided in the junction of the foundation and walls, cracks can be seen throughout the joints of the foundation and walls. Whenever this type of crack is formed, it becomes very difficult to repair, even with grouting techniques. This design should be made accurately to ensure non-cracking at the joints of the foundation and walls.
- Due to Foundation Settlement: Whenever a foundation settles due to soil settlement or due to a rising water table, the wall settles along with the foundation. As a foundation with walls is a rigid structure, due to the settlement of the foundation, horizontal cracks can be formed throughout the walls. To do this, foundation experts must be hired to investigate the soil properties from the groundwater table. If cracks appear on the surface of the walls, grouting may be adopted to ensure that the crack does not propagate.
- Due to Growth of Tree Roots: As the growth of tree roots is a potential reason for serious foundation failure, it can adversely affect the foundation walls as well. As a crack appears on the surface of the foundation, it may propagate into the wall, resulting in horizontal cracks forming into the wall as well.
Horizontal Crack in Basement Wall
Horizontal cracks can be seen in the basement wall as well. The reason for these types of cracks can be the same as that of the previous one. Although there are some exceptional reasons as well, they are as follows:
Due to Lateral Pressure from Surrounding Soil: This is the most common reason for cracking, especially in a basement wall. As we all know, a basement is a place that remains underground. Thus the basement walls are subjected to lateral pressure from the surrounding soil. If the walls are not structurally strong enough to withstand the lateral stresses coming from surrounding soils, cracks can be seen on the surface.
Although this type of crack first comes under the category of fine cracks, if left untreated, it might propagate, thus resulting in the complete collapse of the basement wall. Also, the repair process for this type of wall is quite difficult as there is no access to do that. So care should be taken while constructing a basement wall.
Horizontal Crack in Foundation Repair Cost:
To repair the horizontal cracks in the foundation, the cost will be the same as mentioned in the “cost to fix horizontal cracks”.
Horizontal Vs Vertical Cracks in Foundation?
Vertical cracks are usually the direct result of foundation settling, and these are the more common foundation issues. Horizontal cracks are generally caused by soil pressure and are normally worse than vertical cracks.
Vertical Foundation Cracks?
They’re usually caused by rains that exert pressure on the foundation or concrete tension in newly built homes (every two years or so). Vertical cracks tend to slant slightly (within 30 degrees). To seal them, water-resistant epoxy or polyurethane injection is applied to the cracks.
Vertical Crack in Brick Wall?
Vertical cracking is typically due to brick expansion (remember, bricks are porous and absorb/release moisture like a sponge). Bricks can grow in size as they are exposed to humidity. As bricks grow, they can cause cracking at the seams of walls.
Vertical Cracks in Concrete Walls?
Usually, a diagonal or vertical crack in the foundation wall is the result of settling in the concrete foundation and is quite common in new construction. Because concrete shrinks while it is cures, these cracks are called shrinkage cracks.
Vertical Crack in Basement Wall?
They’re usually caused by rains that exert pressure on the foundation or concrete tension in newly built homes (every two years or so). Vertical cracks tend to slant slightly (within 30 degrees). To seal them, water-resistant epoxy or polyurethane injection is applied to the cracks.
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