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Types of Underpinning

what are the types of underpinning?

Even when underpinning your concrete slab is the ideal solution to fixing house cracks, finding the right underpinning contractor for the project can make or break your efforts. There is a need for tailored solutions to undertaking foundation repair projects. Each unique method is carefully chosen for the unique situation. Possessing foreknowledge of the various types of underpinning helps you to make informed choices when you hire an underpinning contractor.

The different underpinning methods used to fix your foundation problems include:

Image is of an underpinning in Adelaide by our team Adelaide Underpinning Group
Trench dug for underpinning in Adelaide

Concrete slab underpinning

This traditional underpinning method uses concrete for foundation repair work. Square Pits are dug spaced throughout the underpinning area, then reinforced concrete is poured into the pits, solidifying underneath the original foundation. If the property is being lifted, jacks are then placed below the footings and used to raise the house back to the desired level. Sacrificial steel is then placed in lieu of the jacks and concrete is poured to ‘pack out’ the new footing supporting the building. This method may be recommended by the engineer depending on the soil profile and how far the building has shifted.

Screw Pile Underpinning

Underpinning with screwpiles, sometimes referred to as screw anchors or helical piles, involves supporting the foundation of a structure by drilling long steel tubes built with a screw head at one end deep into the ground. Often, sandy and clay soils have weak top layers which destabilise the foundations. The piles are installed to the depth determined by the engineer so that they carry the load from the foundation.

Image is of an underpinning in Adelaide by our team Adelaide Underpinning Group

Geo-polymer Resin Injection

It’s a modern method of ground for ground stabilisation, which uses geopolymer resins pumped into the ground to bear the load of the footings. The resin will expand and harden to create a stable and durable sub-surface for your structure. The installation time is short since it requires drilling a few holes for the injection. One of the risks of this method is if, during the process of resin injection a slightly damaged pipe comes in contact with the resin, the pipe may fill with resin, blocking pipes with hardened resin. No traditional underpinning method can be used once resin injection has been performed and not found to work.

Jet Grouting

It uses grout to create a column of grouted soil underneath the foundation for bearing the load of the structure. This technique may destabilise the soil, and it’s effectiveness largely depends on the soil characteristics. If the area cannot be accessed by heavy equipment, this method may not be best.

What to consider when looking for an Underpinning Contractor

The process of engaging the right underpinning contractor for undertaking foundation repair work can be easy if you know these tips for spotting and engaging the right underpinning specialists. Unlike house renovations, underpinning projects are sensitive, which requires specialised knowledge in foundation repair work and dealing with reactive soils.

Here are the tips to help you lend the most reliable SA underpinning specialists:

  1. Interview Multiple Contractors– don’t hire a contractor you meet on the meet on the go. Contact reputable underpinning companies, that way you can filter-out underpinning contractors’ ‘sales talk’ from specialist advice. Weigh the different opinions, before making a decision.
  2. Check for Reviews and Past Experience– this gives you a clear picture of how the underpinning specialistswill deliver on your project, basing on the experience and reviews from customers. In the end, you expect a clean job from them. If you get more complaints, that’s a red flag.
  3. Check for Communication Skills– as underpinning specialists, they are expected to be great communicators to ensure that you are kept well informed until the project is completed. As the property owner, you deserve to be heard so that every proposed solution has your needs in mind. This helps you to check:
  • their level of reliability
  • project timelines
  • their level of professionalism and respect for clients.

Adelaide Underpinning Group excels in these aspects which is why you should consider us for affordable underpinning services.

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