Reinforced Concrete Foundation

Learn what types of it there are and how to reinforce your concrete foundation

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Your house’s foundation is literally the base of the entire building, and depending on how strong and durable the foundation is, your house may or may not serve you long. However, we tend to forget about the foundation in most cases until there are problems with it. And one of the most frequently faced issues homeowners deal with is the need of strengthening the foundation of their home.

What is a reinforced concrete foundation, you may wonder? Today we will explain that to you. In addition, you are going to learn more about the types of concrete construction footings and the ways of building reinforced concrete footing. Finally, we will explain why you should consider reinforcing your home’s foundation in advance.

How to Build a Reinforced Concrete Foundation?

The most important part of the reinforcement is that between the base and the base wall in case the base wall is made of reinforced concrete. In this case, the process of reinforcement of the foundation wall is going to be similar to the reinforcement of a concrete beam. In particular, it will require spreading the loads evenly over the base and preventing the horizontal forces from tearing the foundation apart.

Workers make the foundation of the house
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Also, the foundation wall should be mounted in wooden formwork. The simplest form of reinforcement will be made by placing two steel rods (also known as reinforcement bars) at the bottom of the formwork, detaching some centimeters from the bottom of the formwork and about 2 cm from the sides. 

During the placement of the concrete, it is very important to keep the reinforcement bars firm. This can be done by attaching them to small concrete blocks tied together with the steel wire forming the base. However, you should do it very carefully since the reinforcement rebars are not supposed to be moved when the wet concrete is put in place in the formwork. 

The most robust solution for the reinforcement of the concrete foundation, in this case, would be the construction of an entire steel reinforcement cage for the beam. This construction will use four longitudinal bars in the concrete, two at the bottom and two at the top, and smaller steel bars that will be bent across the longitudinal bars spaced about 30 cm apart.

During the process, you should keep an eye on the concrete because it must always contain and cover the rebars in such a way that it protects them from rusting! But if you need an even more effective solution, opt for strengthening the foundation as a whole. 

Should you choose this method, the reinforcement procedure we have provided and described above may be used in order to strengthen the basic system. Nevertheless, if you opt for this solution, note that it is also the most expensive one! 

 

Concrete Foundations Types

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There are several types of concrete home foundations that every homeowner should be aware of. Like that, you will be able to better understand what reinforcement nuances your particular foundation type might need and what those nuances depend on. 

 

T-Shaped Concrete Foundation

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A T-shaped foundation is a traditional foundation method that is used in order to support a structure. This method of building a foundation is mostly used for homes built in an area where the ground freezes. 

When this method is used, a t-shaped footing is placed below the frost line, and then the walls are added on top of it. Since the footing is wider than the wall, it is providing extra support at the base of the foundation. A T-shaped foundation is placed and allowed to cure. Second, the walls are constructed. And finally, the slab is poured between the walls.

 

Slab-On-Grade Concrete Foundation

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As you might guess from the name of this method, a slab is a single layer of concrete, typically several inches thick. This slab is poured so that it is thicker at the edges, forming an integral footing. Then reinforcing rods strengthen the thickened edge. 

In order to improve drainage, the slab would normally rest on a bed of crushed gravel. To reduce the chance of cracking, a wire mesh is cast in the concrete. A slab-on-grade method is very handy and is best to use in areas where the ground doesn't freeze. However, if you live in an area with a cold climate, this foundation type can also be adapted with insulation to prevent it from being affected by frost. 

 

Frost Protected Concrete Foundation

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If you think about using this method, note that it only works with a heated structure! Frost-protected concrete foundation method relies on the use of two sheets of rigid, polystyrene insulation. One of them is placed on the outside of the foundation wall and the other one is laid flat on a bed of gravel at the base of the wall. 

Such a construction prevents freezing, which is often a problem with slab-on-grade foundations in areas with frost. The insulation holds heat from the structure in the ground under the footings and prevents heat loss from the edge of the slab. This heat keeps the ground temperature around the footings above freezing.

Now you know what types of concrete foundations exist and what makes them distinct. Also, you now have at least a basic understanding of when each of these foundation types should be used. Like that, if you are going to build a house, for example, you will be able to figure out what kind of foundation you should get.

 

Why Should Foundations Be Strengthened?

If you live in your own home and you have never had any problems with your house’s foundation, you are lucky! And probably, you have never asked yourself why the home foundation should be reinforced at all. However, doing this is very important, and in fact, every homeowner should get their foundations strengthened!

See, the foundation of a home is literally what the entire building rests on. It keeps the whole construction stable and strong. So apparently it is supposed to be a long-lasting and durable base that can withstand any weather conditions and other external factors and elements, such as snow, rain, flood, extra weight, etc.

However, if your house is built on land with unstable soil, any changes in the soil below your home can lead to shifts in the foundation! This can happen for different reasons, for example, because of floods or added weight (e.g. if you added an extra storey on top). Sometimes, when the foundation is not reinforced, it cannot handle such challenges and shifts itself and breaks.

This is why it is strongly recommended that you reinforce your house before any damage occurs. Luckily, there are various methods for doing so, which means that you can choose the one that will suit your budget and be the most appropriate for your home. Nevertheless, it would still be better if a structural engineer or a residential contractor makes specific recommendations for your home. Like that, you will know for sure what method of reinforcement your home needs and how much it might cost you to do it.

 

In What Cases You Should Consider Reinforcing Your Home’s Foundation

You might be wondering why you would have to reinforce your house’s foundation if there are no visible signs of damage right now. Many people think the same, however, foundation damage is a tricky thing! It never occurs suddenly. Instead, it develops slowly, progressing and weakening your home’s foundation gradually. As a result, the condition of your house’s foundation is altered and its condition is way less good than it was before.

So when should you start getting worried and consider reinforcing your foundation? There are several clear signs that can help you catch that moment. Below, you can learn more about each of them so that you know what you should look for.

 

The Foundation Of Your Home Has Cracks

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This is the very first and the most obvious sign of a damaged foundation! If there are cracks, your foundation is definitely in need of repair and reinforcement. Cracks are also very tricky since first of all, hidden cracks occur, which are very easy to miss, and then, visible ones typically appear afterward. But those big ones are already a mayday sign! 

Moreover, if there is any crumbling of the exterior walls, this is another concern! There could be signs of damage inside your home as well, for instance, a basement may show signs of hairline fractures and visible damage. This is why the very first thing you should do is inspect the walls of your basement (if you have it) and see if your home’s foundation has any visible cracks. 

 

You Might Have Warped Ceilings and Walls

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When you want to figure out whether your foundation is damaged or not, take a closer look at your interior walls. The interior home walls typically provide way more information about the state of the foundation of the building, letting us know what’s going on underneath the building. Besides, it is the fastest way to learn how it’s going on down there! 

So if you see that the interior walls or the ceiling are no longer flush and flat, this can show that a house shift has occurred. You can also find it out by looking at the corners of the rooms. If they no longer match well, there is clearly a problem. If the corners, molding, joints, and ceiling are no longer flush, consider reinforcing your foundation! 

 

There Is Water Damage

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Quite often, various kinds of foundation damage take their origin from water. For example, if water does not drain properly away from the building, this can lead to a damaged foundation. And if your home has a concrete foundation, it can take a certain amount of moisture buildup before it begins to crumble and deteriorate.

 

Consider Other Structural Signs Of Damage

Crumbling walls and uneven ceilings are not the only signs of a damaged foundation.  A few other structural signs also need to be taken into consideration:

  • Sloping stairs
  • Windows that have lost their square shape
  • Floors that are no longer level
  • Doors that are not aligned properly

If you see any of them in your home, note that they are also signs of problems with the foundation. You may notice these easily when objects roll on the floor in one direction, or the doors do not stay closed tightly. 

Now you know more about the concrete foundation and certain nuances of its construction. In addition, we told you how you can identify any problems with your home’s most important part in order to fix them in time. With all this in mind, maintaining your concrete foundation will be somewhat easier for you now. And remember that the foundation of your house should be taken care of properly! Do regular checks to spot any signs of upcoming damage (e.g. cracks or crumbling). Like that, you will avoid worse damage in the future. 

 

How to repair the foundation of the house?

Facts

  1. First Reinforced Concrete Skyscraper: The Ingalls Building, located in Cincinnati, Ohio, was the first skyscraper to be built using reinforced concrete in 1903. It's 16 stories high and still stands today, attesting to the durability of reinforced concrete.
  2. World's Longest Concrete Foundation: The Great Wall of China, a UNESCO World Heritage Site, is built on the largest known concrete foundation. Ancient builders used a type of early concrete made from lime and rice, which has stood the test of time.
  3. Strength in Numbers: The compression strength of typical concrete is around 3,000 to 7,000 psi (pounds per square inch), but when reinforced with steel, the tensile strength can reach up to 60,000 psi, illustrating the synergy of steel and concrete.
  4. Burj Khalifa's Massive Foundation: The Burj Khalifa, currently the tallest building in the world, is anchored by a reinforced concrete foundation consisting of 192 piles buried more than 50 meters deep. The foundation alone required over 58,900 cubic yards of concrete!
  5. Earthquake Resistant: The use of reinforced concrete foundations in seismic zones has significantly reduced the risk of building collapse during earthquakes. Reinforced concrete can flex and absorb the energy of an earthquake, enhancing the safety and resilience of structures.
  6. The Use of Rebar: The use of rebar (reinforcing bar) in concrete foundations significantly increases the concrete's resistance to tension forces, which is why it's used in almost every type of concrete foundation today.
  7. Environmental Impact: Reinforced concrete foundations have a lesser environmental impact compared to other construction materials. They use natural, abundant resources (water, aggregate, and limestone), and the reinforcement typically consists of recycled steel.
  8. The Hover Dam: Built in the 1930s, the Hoover Dam was one of the most ambitious projects of its time, using an astounding 3.25 million cubic yards of concrete for the dam and an additional 1.11 million cubic yards for the power plant and other facilities.
  9. Record Concrete Pour: The Guinness World Record for the largest continuous concrete pour is held by the Three Gorges Dam in China. The dam required 16 million cubic meters of concrete.

 

Reinforced concrete foundations truly are the unsung heroes of modern infrastructure, supporting the world's most impressive structures and standing the test of time. 

History

The story begins in the early 19th century with a French gardener named Joseph Monier.

Monier's job was to design and build flower pots that were both durable and aesthetically pleasing. However, he found the earthenware and metal pots available in his time to be lacking. The former was fragile and the latter prone to rust. This inspired him to think outside the box, leading him to experiment with embedding iron mesh into his concrete pots. The result was a sturdy, weather-resistant pot. This simple invention marked the birth of reinforced concrete.

Recognizing the potential of his discovery, Monier patented his reinforced concrete design and began to explore other applications for his new material. In 1867, at the Paris Exposition, Monier showcased a small reinforced concrete bridge, marking the first known architectural use of this robust material. The idea quickly spread across Europe, eventually reaching the United States by the late 19th century.

Fast forward to 1903 in Cincinnati, Ohio, the construction of the Ingalls Building marked a significant milestone in the use of reinforced concrete. The 16-story building was the first skyscraper to be built using reinforced concrete, proving to the world that reinforced concrete could be used for large-scale, high-rise constructions.

This method of construction gained momentum, leading to the extensive use of reinforced concrete foundations in building architecture. Today, the strength and durability of reinforced concrete make it the material of choice for foundations in a vast range of structures, from residential homes to the tallest skyscrapers.

A standout example is the Burj Khalifa in Dubai. The structure, which stands as the tallest building in the world as of my knowledge cutoff in 2021, is supported by a reinforced concrete foundation that consists of 192 piles, each buried more than 50 meters deep. The construction of this foundation required over 58,900 cubic yards of concrete.

Expert Advice

Plan Ahead: Proper planning is essential for a successful foundation project. This includes understanding the soil type, load-bearing capacity, and possible environmental conditions, such as ground movement or frost heave.

Choose the Right Mix: The concrete mix used for foundations must have the right proportion of cement, sand, and aggregate. The choice of mix will depend on the site conditions and the load the foundation will bear. Consult a structural engineer for professional advice.

Reinforcement Matters: The steel reinforcement in a concrete foundation is crucial to its strength and durability. The size, type, and positioning of steel rebars must comply with structural designs and local building codes.

Professional Formwork: Formwork is the temporary or permanent molds into which concrete is poured. It must be correctly set up to ensure the concrete maintains its shape while setting. Professional help is often advised for this intricate process.

Consistent Pouring: When pouring the concrete, avoid interruptions as much as possible. Consistent pouring ensures uniform strength throughout the foundation.

Proper Curing: Once poured, concrete needs time to cure to reach its maximum strength. Keep the concrete moist and protect it from extreme weather conditions during this period, which usually lasts about a week.

Regular Inspection: Regular inspections by a certified structural engineer are vital during the construction of a reinforced concrete foundation. This ensures adherence to the design specifications and identifies any potential issues early.

Safety First: Remember, safety is paramount. Always use protective equipment such as gloves, boots, and helmets. Also, make sure the construction site is safe for workers and visitors alike.

Safety

  1. Personal Protective Equipment (PPE): Workers should always wear appropriate PPE, including safety helmets, gloves, high-visibility clothing, steel-toe boots, and eye protection.
  2. Training: Workers should be adequately trained to handle all machinery, tools, and materials safely. This includes understanding the safe use, potential hazards, and emergency procedures related to the equipment.
  3. Inspect Equipment: Regularly inspect and maintain all construction equipment. Defective tools and machinery should be reported and repaired or replaced immediately.
  4. Handling Materials: Proper techniques should be used when lifting and handling materials to prevent injuries. Mechanical aids should be used for heavy lifting.
  5. Formwork Safety: Formwork must be designed and constructed by competent persons. It should be adequately supported and braced before concrete is poured.
  6. Reinforcing Steel Safety: When cutting or bending reinforcing steel, proper equipment should be used to prevent injuries. Any protruding steel should be clearly marked to prevent accidents.
  7. Fall Protection: Where there is a risk of falling, protective measures such as guardrails, safety nets, or fall arrest systems should be in place.
  8. Slab Edge Protection: Provide edge protection around the slab edges to prevent falls and to stop tools and materials from falling to lower levels.
  9. Proper Ventilation: If work is being done in confined spaces, ensure there's proper ventilation and air monitoring. Workers should be trained on confined space entry procedures.

Frequently Asked Questions

How Often Shall I Check My Home’s Foundation?

This should be done every season to make sure the foundation is doing well. Especially if you have severe weather conditions like hurricanes, floods, or heavy snowfalls/snowstorms.

Does A Foundation Have A Fixed Lifespan?

If you are diligent in caring for your foundation repair with regular maintenance and professional service when needed, it may last ten years or more.

What’s The Strongest Foundation?

Foundations are mostly constructed from strong material so they can hold the house in place. Therefore, they are generally made up of concrete which is the strongest construction material.

What Is A Reinforced Concrete Foundation?

A reinforced concrete foundation is a structure that combines concrete with steel reinforcement bars (rebars) to create a strong, durable base for a building. By adding reinforcement, the foundation can better handle the weight, weather conditions, and other external factors that it may face throughout its lifetime.

 Reinforced concrete foundations are widely used and known for their strength and durability.

How Do You Build A Reinforced Concrete Foundation?

Building a reinforced concrete foundation involves creating a wooden formwork, placing steel rebars in the correct positions, pouring concrete into the formwork, and allowing it to cure. The reinforcement bars need to be secured in place, and the concrete must cover and protect them from rusting.

The process is accurately described, although there may be variations depending on specific requirements and local building codes.

What Are The Types Of Concrete Foundations?

There are three main types of concrete foundations: T-shaped, slab-on-grade, and frost-protected. Each foundation type has its own unique features and is suited for different climates and building requirements.

These are indeed the primary types of concrete foundations, but there may be variations or additional options depending on the specific project.

How Is The Reinforcement In Concrete Foundations Designed?

Reinforcement design depends on factors like load-bearing capacity, soil conditions, and foundation type, with rebar size and spacing determined accordingly.

What Is Steel Reinforced Poured Concrete Foundation
  1. Definition: Steel-reinforced poured concrete foundation is a type of foundation that combines steel reinforcement bars (rebars) with poured concrete, providing enhanced strength and durability for the structure.
  2. Construction process: Excavate the site, install formwork, place steel reinforcement bars, and pour concrete into the forms, allowing it to cure and reach its required strength.
  3. Benefits: Offers increased structural integrity, resistance to cracking and shifting, and improved load-bearing capacity compared to non-reinforced concrete foundations.
  4. Costs: Generally more expensive than non-reinforced concrete foundations due to the additional materials and labor required, but the long-term benefits often outweigh the initial investment.
  5. Timing: Construction time may be slightly longer than non-reinforced concrete foundations due to the added complexity of installing reinforcement bars and ensuring proper placement.
  6. Technical details: Rebar size and spacing, concrete mix, and curing time are critical factors to consider for optimal strength and durability. Consult local building codes and a structural engineer for specific requirements.
  7. Considerations: Soil conditions, climate, and structural loads will impact the design and construction of a steel-reinforced poured concrete foundation. Proper planning and professional guidance are essential for successful implementation.
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Comments

Rod McClure:
Is a thicker foundation better? We are now going to start building our house and we can’t decide how thick the foundation should be. Since I’m not aware of all these construction things, I thought you guys might help.
Angus Ullrich:
Well, in general, heavier siding materials require thicker foundation walls. Wood, metal, and vinyl-sided buildings require a foundation wall thickness of eight inches. Brick veneer requires a foundation wall thickness of 10 to 12 inches, leaving room for a ledge to support the brick. So you should decide depending on what your home will be made of and how may storeys it will have.
Jessica Armstrong:
I’m gonna buy a house but it’s pretty old so I have concerns about the foundation. Is there any way to check the condition of it?
Gerry Powlowski:
Well, as far as I know, you can scan the foundation of a house, they use a special tool for it (don’t remember its name, sorry). Also, I’d recommend you examine the interior walls for any crumbling and cracks. See if the windows and doors are aligned and the floors are even. Nothing should be leaning or crumbling ideally.
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