Foundation Repair | a detailed overview

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Foundation repair needs to be done as per the damage level to the foundation. Up to a certain extent, we may observe the condition of the foundation. If things get worse, we may need to attend to that.

At the initial stage, we may have signs of foundation damage by cracking of the partition walls such as brick walls. At this stage, we shall attend to this matter and an investigation shall be done as to how brick walls are cracked.

Whether is a thermal crack, foundation settlement crack or it is due to the failure of the foundation shall be investigated and the cause for the cracking should be known.

What are the main reasons for foundation failures or foundation cracks?

Causes of Foundation Damage

The following causes can be highlighted.

How to Identify Foundation Damage or Foundation Cracking

This can be identified with the warnings provided. Accordingly house foundation repair can proceed after identifying the exact damage.

  • Cracking in the partition walls such as brick walls
  • Excessive settlement of the building
  • Formation of the gap between soil and ground slab
  • Cracking in the structural elements

Foundation Failure Methods

Foundation could fail structurally or geotechnically.

Structural failure is caused by the structural damage to the foundation and geotechnical failure is caused by the failure of the soil or the supporting ground.

When a foundation is failed initially, there will be warnings in the form of cracks in the foundation. Carefully examination will enable us to find foundation cracks and then we can do the foundation crack repair.

In summary, here we discuss foundation crack repair, providing additional support and ground improvement methods to avoid foundation failures.

Special attention shall be made to the foundation repair cost when the type of foundation repair method is selected.

Foundation Repair

The nature of the defect leads to the selection of the suitable type of foundation repair method.

Sealants

One of the most common types of repair methods in construction. This is not limited to the foundation, it can be used to repair other types of defects.

Sealant crack repair methods are used to repair the cracks that appear on the surface of the foundation. Further, the crack shall not be at a critical level causing foundation failures. Foundation crack repair shall only be done under the guidance of a reputed structural engineer.

  • Firstly, the surface shall be cleaned properly
  • Prepare the crack edges and clean the crack
  • We may insert the backer rod depending on the nature of the crack
  • Then apply the sealant.
Steel Piers

Though steel is identified as a corrosive material, it can last very long years if we used proper construction methods. Correctly treated steel piers for corrosion can be used the stronger the foundation where there are possible failures.

Further, it should be noted that having adequate oxygen and moisture is the key to corrosion of the steel. Inadequate oxygen under the ground could also delay the process of steel corrosion.

The use of steel piers to support the foundation shall be done in consultation with a reputed structural engineer.

Poured Concrete Piers

When additional support is required to maintain the stability of the foundation, concrete piers could be used.

This is a cast-in-situ concrete pier and it is can be constructed at the relevant locations as required to support the structure. In general, the depth of the pier could be in the range of 1.5-3m. The depth shall be determined as per the condition of the ground.

The diameter of the poured concrete pier could be decided based on the applied loads. Generally, it may be about 300mm.  Further, the diameter of the pier could be increased at the bottom to obtain high bearing pressure.

Bell Concrete Piers

They are also used for the same function as the poured concrete piers. The behaviour of both of them is similar.

The sample of this pier is like a bell and therefore, this name is given.

We may construct the bell concrete piers the same as the poured concrete piers and a reinforcement cage will be provided based on the structural requirements.

Slab Jacking

When there is an issue in a part of the structure, we may attend to that particular area and maintain the stability of the structure. In this kind of situation, if the slab is properly constructed, we can do the slab jacking to stabilise the structure.

Supports will be provided to the slab to control the vertical movement of the structure. To proceed with this method, the slab should have adequate structural capacity.

These kinds of foundation repair methods are a bit difficult to adopt and also this is not a kind of foundation repair method. It is a method of creating alternative load paths.

The above methods mostly can be applied in house foundation repair. Instead of foundation repair, ground improvement can also be done. You may also refer to the article underpinning the art of foundation repair.

Another method of Ground improvement as an alternative to foundation repair.

Foundation Improvement by Grouting 

The following methods can be adopted.

  • Cement Grouting
  • Chimerical Grouting
  • Jet Grouting 
  • Compaction Grouting

These methods are more useful when in granular soils. Therefore, the use of these methods depends on soil types. Further, attention shall be made to the foundation repair cost when selecting these methods.

In addition, other foundation repairs of major scale could also be done. In such situations, if the structure is having higher loads piling methods could be used.

  • Driven piles
  • Jacket piles
  • Smaller diameter piles
  • Root piles and reticulated root piles
  • Bored piles

One of these types of foundations may be in the existing structure. Therefore, though the construction of piling may be difficult, depending on the nature of the structure and the requirement, we may adopt a suitable method to improve the foundation.

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