When you start something you need the best foundation to succeed. This rule is relevant to a house. Because when you start to build a house it requires the best house foundation for better construction.
If you fail with the base, your house construction can fail. So pay close attention to build the best house foundation.
The civil engineering industry has different types of foundations and applications can be various from soil conditions.
However, these types are developed with new technologies. Clay and stones are used in the past and currently, concrete, rubble, and steel are used for foundations.
In this article, I will talk about 13 advanced tips that will help to build the best house foundation for your house. So keep reading…
#01 Types of house foundation
All foundations are categorized into main categories. These are,
- Shallow foundations
- Deep foundations
Shallow foundations are the general foundation types that we can see simple construction like houses and small buildings.
Deep foundations are complex and technical foundations that use in high rise buildings. However, these are not used in house construction or small buildings. So deep foundations are not important to house owners.
Shallow foundations can categorize into four categories again. These are,
- Isolated footings
- Combined footings
- Strip foundations
- Raft foundations
Isolated footings or individual footings are single footings with a single column. These types are mostly used in the house and building constructions.
When isolated footings two or more are combined from each other that call as combined footings. These are the same as isolated footings but their structural designs can differ. And combined footings are applying to house and building foundations when it has special requirements.
Strip foundation base wall wider than typical walls. That wider base wall spread the building weight into the ground.
Raft foundation that uses when a building has heavy load and soil has a low bearing capacity. However, raft foundations not use in the general house foundation.
#02 Structural design for house foundation
What is the best foundation for a house?. This is the main problem that wants to build a house. However, we can’t decide what is the house foundation type that uses to our house.
We have to take professional service for house foundation design. Because structural engineers decide which foundation type needs to the house and they will design it. And the structural design is not a simple thing that can be ignored.
The structural designers come to your land and they will check the soil condition of your ground. Then they check the architectural drawings and design the foundation according to drawings and soil conditions.
However, you should talk about house foundation costs with structural designers. Because they need an idea about your budget before doing their design.
What are they design?.
The structural engineer decides suitable materials to the ground and that helps to stabilizes the building. Often this can be concrete. And then they are design size of footings, columns and ground beams.
Excavation depth is another major part of the structural design. Excavation height can be various with soil conditions of the land and size of the building.
#03 Soil testing for house foundation
Some house owners are ignoring soil testing. However, in large civil engineering projects, soil testing is the most important thing before starting the project.
The soil has different bearing capacities depending on the location.
In geotechnical engineering, bearing capacity is the capacity of soil to support the load into the ground.
When the house foundation design doing without soil testing, it can be over deign or poor design.
However, this is not a house owner’s job. Your structural designer will recommend if it needs to your design. But you should know how important it.
There are five types of soil testing methods.
- Moisture content test
- Atterberg limits tests
- The specific gravity of soil
- The dry density of soil
- Compaction test (Proctor test)
Moisture content test is that use to identify the water ratio of the soil. It is an important test in the construction of a house foundation.
Atterberg test that uses to identify the critical water content of the fine-grained soil sample. Atterberg provides the three limits for it and these limits are show the quality of soil in different conditions.
The specific gravity of the soil is the ratio of water to the unit weight of soil.
The weight of soil particles of the given soil sample, that is called dry density of soil. However, the dry density of soil can differ with the void ratio and the specific gravity of soil.
Proctor test or compaction test that uses to test the compaction quality of the soil. This is the main parameter that helps to find the bearing capacity of the soil.
This is a simple guide for soil testing to understand why important it.
#04 Setout the building according to drawing
When you complete the soil testing and structural design, then you should turn to setout the building on your land.
Again, this is not a house owner’s job. Because the house owners haven’t the skill to setout a building in the right way.
When you complete the mentioned task above, then an architect or architectural designer will come back to your land and will setout the building foundation and footings.
It has a lot of technical processes and should be careful when doing it. Architectures know about it and they will do it for you.
However, you can help the architect to find the best location to build your house in your land.
Here is the simple thing you should know about location selection.
- Remember to the selection of the highest location in your land. It will protect your house from the rain waters.
- Easy access to the main road in front of your house.
- As much as possible distance from large trees. Because roots of the trees can damage the structure of your house foundation.
- As much as possible distance from neighboring houses.
- Easy access to services like electric power and water supply.
- Background view from the house after building it.
However, remember to give leadership to designer ideas. Because they have technical knowledge more than you.
#05 Excavation for house foundation
After completing the setting out work in the land, then you should turn to the next step.
Excavation for the foundation.
In the setout process, your surveyor points the building foundation and footings as well. Then you should do excavation the ground to the proper depth.
How to find the proper depth for your house foundation?
In the structural detail drawing, you can see the excavation height of the foundation in the foundation section drawing. However, if you can’t find that detail, it is 1m (3 Feet) for one or two-story houses. But I recommend taking the instruction from your structural designer about it.
You can go with machinery or manpower to excavate the ground. But remember to consider house foundation cost before selecting an option one of these.
While excavating be alert about soil condition of the ground. Because in my experience, I met some lands with different soil conditions in one location.
If you have hard soil like gravel, you haven’t any issue with the ground quality. But if you have loose soil or mud soil you have to go to a much compaction method or backfilling with the aggregate base course (ABC).
#06 Screed concrete for house foundation
How to build a house foundation with structural quality?.
In this case, some contractors are doing huge mistakes from the starting point. Because they are ignoring the screed concrete as unnecessary. But they don’t know the importance of screed concrete.
When constructing the building foundation and footings, screed concrete is doing a major part of it.
What is screed concrete?.
Screed concrete is the 2″ or 3″ thick flat concrete layer that laying down in the ground to prepare the surface.
But it should not be the reinforced or heavy concrete structure. Normally we use 1:3:6 cement, sand, and metal ratio to prepare the screed concrete.
Why need it?
- Surface preparation with screed concrete that will help to set out the footing and columns in their locations.
- Perfect covering length for bottom steel net of the footings. Covering length is the distance of concrete surface to steel surfaces. It helps protect the steel from water and oxide.
- Work as a waterproofing layer to the main structure.
- Avoid the movement of the main structure while concreting.
- The main part of the structural design.
These are the main factors why need screed concrete under every ground structure.
#07 RRM house foundation
In the past, random rubble masonry (RRM) foundations were used for every building. Because concrete or any other methods were not used at that time.
However, upon arrival concrete and tor steels to the construction industry, random rubble masonry foundation was limit for small constructions.
But this is not completely outdated. Some structural engineers recommend using the RRM foundation to the outer line of the house foundations.
When you build the foundation, then you have to refill the internal area of the house with soil. To obtain a good compaction result, you need a barrier around the house. So you can use a random rubble masonry foundation for it.
Another advantage is, acts as a barrier for rainwater flow on the ground. Because if rainwater comes into the house, it can harmful to the structure of the house.
Outer line ground beams can overload than inner ground beams. So if add random rubble masonry foundation under the outer line ground beams, beams can rest on the RRM foundation.
These are the major factors why you need the RRM foundation for your house. So do not think it as an additional house foundation cost.
#08 Reinforced concrete for columns and footings
Reinforcement is the most important thing in house foundation design. Because reinforced concrete stronger than mass concrete.
What is “mass concrete”?.
When making concrete without tor steel or mild steel, it’s called “mass concrete”. Mass concrete use in screed concrete, floor concrete, etc.
But reinforced concrete is a complex design doing by qualified profession. That means, it is a job of structural engineers as that we talk about early. They will do their job well for you. But you should know how to build a reinforced concrete in the right path.
Structural engineers will design following these items for your foundation.
- Width, length, and height of the reinforced footing and columns. That means the size of the footings and columns.
- Cement: sand: the metal ratio of the concrete. That means the grade of your concrete.
- Type and sizes of the steels that you should use to the foundation.
- Space between each steel bar.
- Cover space for tor steels in the structure.
These all details you can see in the structural drawings and if you can’t understand those details, you can ask from designers for clarity. It will help to supervise your project by yourself.
#09 Tie beams between columns to columns
Tie beams is another crucial reinforced structure in the house foundation. It called “Tie beams”, “Plinth beams” and “Ground beams” according to their application. However, these all are structurally the same.
Normally it has four main bars and stirrups to tie main bars. However, the “number of main bars”, “type, and size of main bars”, “size, and type of stirrups” can be different according to the design. Your structural designers will calculate the building loads and design the size of the beam and type and size of the main bars. Then you can work according to those details.
What are the factors you care should be taken when building the tie beams.
- Size of the beam. This is a design by your structural designer and you should take care of build according to it.
- Type and size of the main bars. Generally, reinforcement steels have two categories. Tor steel and mild steel. You can find that details in your drawings. Normally tor steels notice by “T” or “Y” letter and mild steels notice by “R” or “M” letters.
- Grade of the concrete. Normally use 25G (1:1.5:3) or 20G (1:2:4) concrete grades.
- Size and type of stirrups bars and space between stirrups.
- Covering space for reinforcement.
These details are you can find in the systematic detail drawings.
#10 Concrete curing of house foundation
Every reinforced and mass concretes requires the process of curing. Because it should need to control the loss of moisture in concrete when place the concrete in position.
The cement of concrete takes a few weeks for hydration. So need a good curing method to maintain the quality of concrete. Normally we can cure the concrete by applying the water into concrete surfaces.
Curing time may depend on the weather condition, environment condition, and grade of the concrete. Sometimes it can depend on special requirements from structural designers. However, it will be 7 days to 14 days.
Why you need the curing process?.
The main purpose of curing is to control the hydration and temperature of the concrete.
If you are in a warm-weather situation, you need a good curing process for your house foundation.
Some regions have a warm climate most of the year. So in that area need a good curing process to protect the quality of concrete.
Grade 25 concrete requires a good curing process rather than grade 15 concrete.
#11 Backfilling and compaction
When we think about how to build a house foundation in the right way, we can’t ignore backfilling and compaction. Because backfilling and compaction is the most important part of the construction project.
Backfilling should do after excavation when the soil compacted into the foundation trenches and footings.
There are have many different ways to backfill and compact the house foundation. here are the main three factors you should need to remember.
- Backfill in the layer by layer.
- Water ratio.
When you backfill the soil into footings and trenches, remember to fill it layer by layer. Because it will help to better compact. The layers can be 100mm or 150 mm as well.
Another main factor is compacting. After backfilling the footings and trenches with small layers, then you can compact it by hand or using a vibrating compactor. However, when using a vibrating compactor, remember to take skill person service for it. Because it can be harmful if it doing without skill.
The other thing is the water ratio of soil. Be sure to apply water to soil when laying it. Because the soil requires proper moisture content for good compaction.
#12 Anti-termite treatment for house foundation
Anti-termite treatment is another most important part of a construction project. This is an essential part of large scale projects, but in house construction projects we can see some house owners ignore this part.
But it is not a good thing.
The purpose of anti-termite treatments is giving to a chemical barrier for sub-terrain termites.
However, this is a specialized job working with harmful chemicals and machines.
“Chlorpyrifos 20 EC” and “Lindane 20 EC” are that use as a chemical for anti-termite, but it can be different by region and government rules.
This has two main categories according to their application period.
- Pre-construction treatment.
- Post-construction treatment.
Pre-construction anti-termite treatments are that doing in the ground preparation stage. When excavating the ground for footing and trenches, then apply the chemical to sides and bottoms surfaces in the footing and trenches. And after ground preparation for floor concrete, it can do as well.
When identifying the reasons for chemical treatments after building the foundation, then we have post-construction treatment methods. However, in this process, we have to drill the concrete structures to apply the chemicals into the underground soil.
#13 Recheck the house foundation
OK! Now we are in the final stage. After building the house foundation we can recheck it by our self. However, we should need to check everything again and again during the construction stage.
But after building the foundation we can check every dimension according to the drawings. because if happen any mistake we can correct it before starting the build of other structures of the house.
You can check following these items by your self.
- Every dimension according to the drawings.
- Beam and columns size according to the structural details.
- Any damages to the house foundation.
- The vertical and horizontal alignment of the foundation.
After checking the foundation by your self, then you can call to architectures and structural designers for the professional recheck process. It is their responsibility.
What should do if happen any mistake?
It depends on the nature of the mistake.
Sometimes we can correct the mistake by doing simple treatments for the structures. For example horizontal alignment mistakes of the structure. If it happens, we can break the concrete and align the structure.
However, sometimes we have to change the part of the design of the house. So remember to carefully when build the house foundations.