Introduction of Foundation for House
- Foundation is one of the most important parts of the Building on which the whole Structure is rest. Foundation is a very essential part of a building which provide a base to the structure.
- In this article, you will get to all about the foundation, Types of house foundation and how to build a house foundation.
Definition of Foundation
- Foundation is the part of the superstructure which is one of the most important parts of the structure. It is the lowest part of the structure below the ground level which provides a base for the building.
- The main function of the foundation is to receive the total load of the structure and transmit it safely to the underground soil strata without any excessive settlement of the soil.
Purpose of Providing Foundation to the Structure
The function of the foundation is as follows
- The main function of the foundation is to distribute the total weight of the structure over the larger area.
- The foundation is constructed to provide a proper level surface for the construction of the superstructure of the building.
- There may be chances of the settlement of the structure due to heavy loading on the subsoil. The foundation helps to prevent the unequal settlement.
- The foundation provides the stability to the structure and prevents overturning by taking the total weight of the structure deep into the ground.
- The foundation is not provided to support the load of the structure but in fact, it serves as a means to transmit the load of the building to the soil below the foundation.
- Foundation is provided to prevent the lateral movement of the structure and increase structural stability.
Requirement of Good Foundation for the Structure
The following are the essential requirements of the good Foundation
- Location of the Foundation.
- Stability of the Foundation.
- Durability of the Foundation.
- Settlement of the Foundation.
1. Location of the Foundation
The foundation should be located such that it can able to resist any unexpected influence likely to appear in the future to the structure.
So care should be taken while designing the layout of the foundation.
2. Stability of the Foundation
The structural stability of the foundation of the building is a very essential requirement for the construction of a good Foundation. The foundation should be stable and save to resist any settlement.
The foundation which should be rigid to take the superimposed load which may unevenly be distributed.
3. Durability of the Foundation
The design and construction of the foundation are done in such a way that it should be durable and resist the heavy load of the structure.
4. Settlement of the Foundation
Settlement of the foundation of a building depends upon the bearing capacity of the soil. The soil Strata where the position will be constructed should be more rigid and compact to avoid the settlement of the foundation.
The foundation should be constructed such that it should not settle under the heavy superimposed load.
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Why Different Types of Foundations Are Used in Construction?
The bearing capacity of the soil depends upon the site conditions. It varies from site to site. Engineers have to design different types of foundation as per the bearing capacity of the soil and the site conditions.
Hence it is not possible to construct the same type of foundation to every site. Depending upon the soil profile, size and the load of the structure different types of foundations are used.
If the foundation of this structure is constructed without understanding the ground conditions of the site then it may lead to the failure of the foundation.
Once the little failure of the foundation takes place then it is difficult to improve the situation.
Types of House foundations
The house foundations are classified into mainly two types
- Shallow Foundation
- Deep Foundation
#1. Shallow Foundation
Shallow Foundation is the type of house foundation whose depth is less than or equal to the width of the foundation. The shallow Foundation is economical and popularly used Foundation construction of lightweight structures.
The shallow foundation is the most common type of foundation which can be laid using open excavation. The shallow Foundation is used generally for a depth of 3.5 to 4m.
This type of foundation is provided for the structures of moderate height which are built on sufficiently formed dry ground.
There are different types of Shallow foundations
- Wall Footing
- Isolated Footing
- Combined Footing
- Inverted Arch Footing
- Cantilever Footing or Strap Footing
- Grillage Footings
- Raft or Mat Foundation
The brief description of the types of Shallow Foundation are as follows
1.1. Wall Footings
There are two types of wall footing which are used in the house foundations are Simple wall footing and stepped wall footing. For the construction of the lightweight structures or temporary structure, the simple type of footing is used. The simple footing has concrete with below the walls and there is no steps are provided.
In the case of the heavy load structures, the wall spread step by step till the foundation level is reached. In the case of step footing, the area of the wall is increased to transmit the load on the larger area of soil.
The simple wall footing is used in the construction of compound walls and lightweight structures whereas the stepped footing is used for the load-bearing structure.
1.2. Isolated Footing
The isolated footing is used to support the individual and columns. Isolated footing either be stepped footing or have a projection in the concrete base.
The isolated footing is generally used in the construction of the ordinary-buildings up to five storeys. The isolated footing is one of the most economical types of foundation.
1.3. Combined Footing
Sometimes there are two columns are located very near to each other, in such cases, the footings of both columns overlap each other. That’s why it is necessary to provide a combined footing for both the columns.
The condition which should be fulfilled in this type of footing is that the centre of gravity of the column loads and the centroid of the footing should coincide.
There are two types of combined footing one is rectangular combined footing and second is the Trapezoidal combined footing.
The rectangular combined footing is used when the loads on the two columns are equal. The trapezoidal combined footing is used when the lots on the two columns are unequal.
1.4. Inverted Arch Footing
1.5. Cantilever Footings or Strap Footing
Cantilever footing is also known as strap footing. This type of footing is used when the column is located near the boundary of the plot and it is not possible to permit the footing of that column to exceed beyond the plot boundary.
The strap beam is provided in this type of footing which helps to co-ordinate and support the load of the column which is located on the boundary. The strap beam helps to connect two columns with each other.
1.6. Grillage Foundation
Grillage Foundation is used to transmit the heavy load from the Steel columns to the soil which has low bearing capacity. This type of foundations is lighter and economical.
1.7. Raft or Mat Foundation
- Raft Foundation is a type of foundation which consists of a thick reinforced concrete slab. this type of foundation covers the entire area of the bottom of the structure on the subsoil.
- Raft foundation is suitable where the soil on the ground is soft and has low bearing capacity.
#2. Deep Foundation
The foundations are used where the soil below the structure within reasonable there is not capable of supporting the load of the structure. Hence it is necessary to transmit the load of the structure at a greater depth.
The function of the Deep Foundation is to transmit the load of the building to the firm layers deep inside the ground.
The deep Foundation is categorised into two types
- Pile Foundation
- Well Foundation
2.1. Pile Foundation
2.2. Well Foundation
What Is the Best Foundation for a House?
The strongest foundation for a house is very important in the construction of the structure because the foundation is one of the most important part of the construction. If the foundation is strong and rigid then only it can carry the total load of the Building.
If the foundation of the structure is not properly designed and it is not enough to carry the load of the structure so there is no advantage of investing money on the superstructure of the Building.
That’s why it is very essential that you should select the best house Foundation. The care should be taken that the foundation should be constructed with strong building materials.
The building materials which are used in the construction of the foundation should be tested. The material should pass all the norms which are given by the Indian standards.
The best house Foundation should be constructed from the strong building material so that it will give maximum structural stability to the building and hold the house during the cyclone and earthquakes.
What Is the Strongest Foundation for a House?
The type of foundation suitable for the construction of the structure depends upon the type of soil available on the site and the type of building which we have to construct.
For the construction of the lightweight or temporary structure, Shallow Foundation is used whereas for the construction of the high rise Buildings deep foundations are used.
How to Build a House Foundation Step by Step?
Step 1: Selection of the Construction Site
Selection of the best site for the construction of the foundation is very important. The bearing capacity of the soil is checked which is available on the site.
Step 2: Marking the Layout of the Foundation
The size of the foundation is marked on the ground as per the measurements which are given in the drawing.
Step 3: Excavation of the Trenches
Destination work is done as per the measurements given in the drawing. It is necessary that the supervisor should inspect whether the excavation and the depth of the foundation are as per drawing or not.
Step 4: Anti-Termite Treatment
Anti-Termite treatment is very important to protect the house Foundation from the term attack. It is necessary that the soil around the house Foundation should be treated wale up to the plinth level with appropriate chemicals and Anti-termite treatment.
Step 5: Providing PCC to the Base of the Trenches
The next step to the construction of the building foundation is the composition of the excavated soil top layer and providing a layer of plain cement concrete on it.
Step 6: Installation of Formwork
Step 7: Pouring of Concrete
Step 8: Curing of the Concrete
Curing is very necessary which will help to gain strength. Curing should be started early stage and continue for a sufficient period of time which will ensure your the desired strength of the concrete.