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What is underpinning, and why is it needed?

Underpinning is a technique to fix the foundation issues by excavating the moving soil that is removing the support and hence causing the building to move. Such a situation is called subsidence which can ruin your building’s foundation. Underpinning is the best process to fix subsidence issues in your foundation but the cost of underpinning a house can be different in different scenarios. .

When do you need underpinning?

There can be many reasons for needing underpinning for your foundation. A surveyor or a structural engineer must have suggested to you that you need underpinning. There can be different reasons for that as follows:

Poor Soil quality:

The faulty drains and such temporary issues can drive your attention towards underpinning. But these temporary issues are caused by poor soil quality. So, if you live in an area where the soil is permanently moist, moving, or cracking, it means that your house foundation needs underpinning, and you must not delay any further to get it done.

Excavating soil underneath the building:

Another reason when underpinning becomes a must is the excavating soil underneath the building. If you live in a mining area, this is a common issue that you may face. In the mining areas, the soil underneath the buildings can easily collapse and cause cracking in the walls of the buildings built on such soil.

Increased load:

Sometimes, when you try to extend the building on the same foundation, it can weaken the foundation, and hence it causes cracking in the wall. If you are planning to extend your building, you must underpin the foundation so that you can be safe from cracking and foundation damage in the future.

Inappropriate foundations:

It happens mainly in the old buildings that the foundation is not up to the mark. Due to this, buildings have to face various issues. If your building is old enough, it means that you need to underpin your building so that you can avoid any foundation issues.

How can underpinning help you with these issues?

Cracks in the walls, door, and windows frame is the most prominent subsidence signal. These issues need to be addressed immediately because if not, they can affect the entire building foundation.

There are various types of underpinning that you can opt for, but mass concrete underpinning is the most common one. This technique adds more layers of concrete to the existing foundation to make it sturdy. It provides extra support for the load, and it is the best option for extending your building and adding more floors.

The other type of underpinning is called mini piling. This method is used chiefly for the eras where soil quality is worst. In this technique, heavy piles of concrete are added below the round of the foundation. In this way, the weak soil is then made strong to hold the foundation and no cracking has to be faced.

What is the cost of underpinning a house?

Here is the most significant concern of the people thinking of underpinning their houses. Cost of underpinning a house can vary depending on different factors as follows:

  • The extent of damage caused by subsidence.
  • The area of damage

Repairing a corner suffering from subsidence can cost you $3,500-$5,000 or sometimes maybe more than that. And you may have to spend more than $8,000-$12,000  for a complete repair of the basement floor.

Furthermore, filling a small crack on the concrete foundation can cost you somewhere between $400-$800. But if you live in an area where earthquakes are just a norm, you may have to spend $1,500-$3,500 for your foundation repairs because anchor bolts will be used in the repair, and these cost more.